Presynaptic cAMP-PKA-mediated potentiation induces reconfiguration of synaptic vesicle pools and channel-vesicle coupling at hippocampal mossy fiber boutons

May combine two claims.

Neither an increase in the number of Ca2+ channels nor a functional modulation of Ca2+ channels accounts for the Pr change upon induction of chemical potentiation.

“However, a previous study and our results show that neither of them accounts for Pr change upon the induction of chemical potentiation (Fig 4D and 4E) [47].”

• cites [47] R Fukaya, 2021, Rapid Ca2+ channel accumulation contributes to cAMP-mediated increase in transmission at hippocampal mossy fiber synapses, Proc Natl Acad Sci U S A sourceDisputed

  The Discussion section, “Increased Ca2+ Concentration at Mossy Fiber Release Sites under cAMP,” favors Ca2+ channel accumulation at release sites as a mechanism of potentiation and says an increase in channel numbers is consistent with the observed cluster expansion. That contradicts the claim that an increase in channel number does not account for the change in release probability. The Results report that forskolin did not amplify the overall inward Ca2+ current, but that does not negate the paper’s proposed local channel-accumulation mechanism. (LLM, conf=0.90)

  Checked by a reasoning model — may be wrong.

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing).

Stimulation of locus coeruleus neurons enhances hippocampus-dependent memory.

“Notably, stimulation of locus coeruleus neurons, presumably releasing noradrenaline or dopamine, enhances hippocampus-dependent memory [105–108].”

• cites [105] T Takeuchi, 2016, Locus coeruleus and dopaminergic consolidation of everyday memory, Nature sourceSupported
• cites [106] KA Kempadoo, 2016, Dopamine release from the locus coeruleus to the dorsal hippocampus promotes spatial learning and memory, Proc Natl Acad Sci U S A sourceSupported
• cites [107] A Wagatsuma, 2017, Locus coeruleus input to hippocampal CA3 drives single-trial learning of a novel context, Proc Natl Acad Sci U S A sourceNot checked — no full text of the source
• cites [108] AM Kaufman, 2020, A role for the locus coeruleus in hippocampal CA1 place cell reorganization during spatial reward learning, Neuron sourceDisputed

  The Discussion (page unavailable) says local, unilateral LC–CA1 stimulation produced place-cell enrichment when paired with a reward, but did not produce a behavioral effect. The paper therefore does not show that its stimulation enhanced hippocampus-dependent memory; it reports a change in hippocampal representation instead. (LLM, conf=0.87)

  Checked by a reasoning model — may be wrong.

  Experimental — accuracy not yet measured

May combine two claims.

Chemical potentiation primarily involves an increase in pool size but also an increase in Pr, reminiscent of hippocampal mossy fiber PTP.

“Thus, chemical potentiation primarily involved an increase in pool size but also an increase in Pr, reminiscent of hippocampal mossy fiber PTP [21].”

• cites [21] D Vandael, 2020, Short-term plasticity at hippocampal mossy fiber synapses is induced by natural activity patterns and associated with vesicle pool engram formation, Neuron sourceSupported

Classified as probably not a substantial claim. May combine two claims.

Isoproterenol is a β1 and β2 adrenergic receptor agonist known to activate adenylyl cyclase via Gs proteins.

“we applied 1 μM isoproterenol, a β1 and β2 adrenergic receptor agonist, known to activate AC via Gs proteins (Fig 2D–2K) [52–54].”

• cites [52] TJ O’Dell, 2015, β-Adrenergic receptor signaling and modulation of long-term potentiation in the mammalian hippocampus, Learn Mem sourceSupported
• cites [53] N Hansen, 2015, Hippocampal long-term potentiation that is elicited by perforant path stimulation or that occurs in conjunction with spatial learning is tightly controlled by beta-adrenoreceptors and the locus coeruleus., Hippocampus. sourcePartly supported

  The Materials and Methods section identifies isoproterenol as a β-adrenoreceptor agonist. The Discussion says β-adrenoreceptor activation stimulates the cAMP/PKA cascade and mentions β1 and β2 receptors, but our copy does not specify that isoproterenol acts at both subtypes or activates adenylyl cyclase via Gs proteins. Page numbers are unavailable in our copy. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites [54] K Kobayashi, 2022, Noradrenaline activation of hippocampal dopamine D1 receptors promotes antidepressant effects, Proc Natl Acad Sci U S A sourceCould not verify

  The Discussion (page unavailable) says D1 and β receptors are coupled to Gs–cAMP signaling, but it does not address whether isoproterenol activates adenylyl cyclase through β1 and β2 receptors. Searches for “isoproterenol” and the claimed agonist mechanism found no passage about the drug in our copy. (LLM, conf=0.73)

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

High-frequency stimulation induces several cAMP-dependent forms of presynaptic plasticity.

“For example, high-frequency stimulation (HFS) induces several cyclic adenosine monophosphate (cAMP)-dependent forms of presynaptic plasticity [21,28–33].”

• cites [21] D Vandael, 2020, Short-term plasticity at hippocampal mossy fiber synapses is induced by natural activity patterns and associated with vesicle pool engram formation, Neuron sourcePartly supported

  The Results sections “Superbursts in GCs Induce PTP” and “Pool Refilling Determines PTP” report that high-frequency stimulation induces post-tetanic potentiation (PTP) at hippocampal mossy fiber synapses and that PTP involves the cAMP–PKA pathway (page numbers unavailable). The cited paper therefore supports one cAMP-dependent form of presynaptic plasticity, but it does not establish that stimulation induces several such forms. (LLM, conf=0.88)

  Experimental — accuracy not yet measured
• cites [28] YY Huang, 1994, cAMP contributes to mossy fiber LTP by initiating both a covalently mediated early phase and macromolecular synthesis-dependent late phase, Cell sourceNot checked — no full text of the source
• cites [29] MG Weisskopf, 1994, Mediation of hippocampal mossy fiber long-term potentiation by cyclic AMP, Science sourceNot checked — no full text of the source
• cites [30] G Tong, 1996, Long-term potentiation in cultures of single hippocampal granule cells: a presynaptic form of plasticity, Neuron sourceNot checked — no full text of the source
• cites [31] JC López-García, 1996, A presynaptic locus for long-term potentiation of elementary synaptic transmission at mossy fiber synapses in culture, Proc Natl Acad Sci U S A sourceSupported
• cites [32] G Maccaferri, 1998, Target-specific expression of presynaptic mossy fiber plasticity, Science sourceNot checked — no full text of the source
• cites [33] M Midorikawa, 2017, Kinetics of releasable synaptic vesicles and their plastic changes at hippocampal mossy fiber synapses, Neuron sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

Biophysical studies often delineate different vesicle pools at presynaptic active zones, but how these pools correlate to vesicle populations in electron micrographs or tomograms remains unclear.

“Finally, biophysical studies often delineate different vesicle pools at presynaptic active zones (AZs), specialized sites of synaptic vesicles fusion and neurotransmitter release [9–13] but how these pools correlate to vesicle populations in electron micrographs or tomograms remains unclear.”

• cites [9] SO Rizzoli, 2005, Synaptic vesicle pools., Nat Rev Neurosci sourceNot checked — no full text of the source
• cites [10] AA Alabi, 2012 sourceNot checked — no full text of the source
• cites [11] E. Neher, 2015, Merits and limitations of vesicle pool models in view of heterogeneous populations of synaptic vesicles, Neuron sourceNot checked — no full text of the source
• cites [12] PS Kaeser, 2017, The readily releasable pool of synaptic vesicles, Curr Opin Neurobiol sourceSupported
• cites [13] J Emperador-Melero, 2020, Assembly of the presynaptic active zone, Curr Opin Neurobiol sourceSupported

Classified as probably not a substantial claim.

Munc13-1/2 are putative markers of primed vesicles.

“and Munc13-1/2, putative markers of primed vesicles [14,42–45,60,61].”

• cites [14] C Imig, 2014, The morphological and molecular nature of synaptic vesicle priming at presynaptic active zones, Neuron sourceNot checked — no full text of the source
• cites [42] F Varoqueaux, 2002, Total arrest of spontaneous and evoked synaptic transmission but normal synaptogenesis in the absence of Munc13-mediated vesicle priming, Proc Natl Acad Sci U S A sourcePartly supported

  The Discussion reports that removing both Munc13-1 and Munc13-2 eliminates readily releasable vesicles and arrests vesicle priming in mature hippocampal neurons. This supports their role as priming factors, but the paper does not establish that either protein serves as a marker identifying primed vesicles. (LLM, conf=0.82)

  Experimental — accuracy not yet measured
• cites [43] F Varoqueaux, 2005, Aberrant morphology and residual transmitter release at the Munc13-deficient mouse neuromuscular synapse, Mol Cell Biol sourcePartly supported

  The Discussion (page unavailable in our copy) identifies Munc13-1 and Munc13-2 as proteins involved in synaptic vesicle priming. It does not establish that they mark primed vesicles; it also reports that some priming at the mouse neuromuscular junction occurs without Munc13 proteins. (LLM, conf=0.82)

  Experimental — accuracy not yet measured
• cites [44] N Lipstein, 2013, Dynamic control of synaptic vesicle replenishment and short-term plasticity by Ca2+-calmodulin-Munc13-1 signaling, Neuron sourceNot checked — no full text of the source
• cites [45] H Sakamoto, 2018, Synaptic weight set by Munc13-1 supramolecular assemblies, Nat Neurosci sourceNot checked — no full text of the source
• cites [60] Z Chen, 2013, The Munc13 proteins differentially regulate readily releasable pool dynamics and calcium-dependent recovery at a central synapse, J Neurosci sourcePartly supported

  The Introduction (page not supplied) describes Munc13 proteins as regulators of vesicle priming, and the section on subsynaptic distributions reports Munc13-1 and Munc13-2 signals at presynaptic sites. The paper does not establish that either protein specifically marks vesicles that are already primed. (LLM, conf=0.83)

  Experimental — accuracy not yet measured
• cites [61] K Grushin, 2022, Munc13 structural transitions and oligomers that may choreograph successive stages in vesicle priming for neurotransmitter release, Proc Natl Acad Sci U S A sourcePartly supported

  The Results section identifies the protein studied as a portion of Munc13-1 and says its C2C domain is required for synaptic-vesicle priming. The Discussion’s three-state model also places Munc13 on vesicles before they are primed. These passages support a role for Munc13-1 in priming, but do not establish Munc13-1/2 as markers of primed vesicles; the paper does not address Munc13-2. (LLM, conf=0.83)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing).

Forskolin is a widely used adenylyl cyclase activator.

“To maximally activate the cAMP pathway, we applied forskolin, a widely used AC activator [28–31,33,48].”

• cites [28] YY Huang, 1994, cAMP contributes to mossy fiber LTP by initiating both a covalently mediated early phase and macromolecular synthesis-dependent late phase, Cell sourceNot checked — no full text of the source
• cites [29] MG Weisskopf, 1994, Mediation of hippocampal mossy fiber long-term potentiation by cyclic AMP, Science sourceNot checked — no full text of the source
• cites [30] G Tong, 1996, Long-term potentiation in cultures of single hippocampal granule cells: a presynaptic form of plasticity, Neuron sourceNot checked — no full text of the source
• cites [31] JC López-García, 1996, A presynaptic locus for long-term potentiation of elementary synaptic transmission at mossy fiber synapses in culture, Proc Natl Acad Sci U S A sourcePartly supported

  The Abstract reports applying forskolin to simulate mossy-fiber potentiation and links that potentiation to protein kinase A. It does not identify forskolin as an adenylyl cyclase activator or say that its use is widespread; searches for those terms found no supporting passage in our copy. (LLM, conf=0.78)

  Experimental — accuracy not yet measured
• cites [33] M Midorikawa, 2017, Kinetics of releasable synaptic vesicles and their plastic changes at hippocampal mossy fiber synapses, Neuron sourceNot checked — no full text of the source
• cites [48] JH Vaden, 2019, The readily-releasable pool dynamically regulates multivesicular release., Elife sourceSupported

May combine two claims.

Biophysical measurements report the coupling distance between Ca2+ channels and release sensors, but the physical correlate of this measure remains undefined.

“Furthermore, biophysical measurements report the coupling distance between Ca2+ channels and release sensors [7,8] but the physical correlate of this measure remains undefined.”

• cites [7] EM Adler, 1991, Alien intracellular calcium chelators attenuate neurotransmitter release at the squid giant synapse, J Neurosci sourceSupported
• cites [8] E Eggermann, 2012, Nanodomain coupling between Ca2+ channels and sensors of exocytosis at fast mammalian synapses., Nat Rev Neurosci sourcePartly supported

  The “Tight coupling at fast central synapses” section describes chelator experiments and modelling used to estimate channel–sensor coupling distance. The paper does not say that the physical correlate of that measurement remains undefined; its “From nanodomains to protein complexes” section instead discusses protein–protein interactions as a possible basis for tight coupling. No page numbers are available in our copy. (LLM, conf=0.82)

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

Transmitter release at central synapses is not constant but undergoes substantial activity-dependent changes.

“Transmitter release at central synapses is not constant but undergoes substantial activity-dependent changes [18].”

• cites [18] HR Monday, 2018, Long-term plasticity of neurotransmitter release: emerging mechanisms and contributions to brain function and disease, Annu Rev Neurosci sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The readily releasable pool often closely correlates with the pool of docked vesicles, but exceptions to this correlation have been observed.

“For example, the readily releasable pool (RRP) often closely correlates with the pool of docked vesicles (i.e., vesicles in the direct contact with AZ plasma membrane) [14] but exceptions to this correlation have been also observed [15–17].”

• cites [14] C Imig, 2014, The morphological and molecular nature of synaptic vesicle priming at presynaptic active zones, Neuron sourceNot checked — no full text of the source
• cites [15] KN Man, 2015, Identification of a Munc13-sensitive step in chromaffin cell large dense-core vesicle exocytosis, Elife sourceSupported
• cites [16] SSH Wang, 2016, Fusion competent synaptic vesicles persist upon active zone disruption and loss of vesicle docking, Neuron sourceSupported
• cites [17] C Tan, 2022, Munc13 supports fusogenicity of non-docked vesicles at synapses with disrupted active zones., Elife. sourceSupported

Classified as probably not a substantial claim.

Previous studies reported a lack of change in coupling distance between CaV2.1 and Munc13-1.

“However, previous studies reported a lack of change in coupling distance between CaV2.1 and Munc13-1 [46,47].”

• cites [46] M Orlando, 2021, Recruitment of release sites underlies chemical presynaptic potentiation at hippocampal mossy fiber boutons, PLoS Biol sourceSupported
• cites [47] R Fukaya, 2021, Rapid Ca2+ channel accumulation contributes to cAMP-mediated increase in transmission at hippocampal mossy fiber synapses, Proc Natl Acad Sci U S A sourcePartly supported

  The Results (gSTED microscopy section) report similar measured peak-to-peak distances between CaV2.1 and Munc13-1 clusters under control and forskolin conditions. But the authors explicitly caution that these measurements cannot exclude subtle changes in physical coupling distance, so an unqualified lack of change in coupling distance overstates the finding. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

May combine two claims.

PKI 14-22 treatment blocked the forskolin-induced increase in Munc13-1 clusters and decreased their number.

“Application of alternative PKA inhibitor, PKI 14–22 [79] similarly blocked the increase in Munc13-1 clusters, and even decreased their number (S9A–S9D Fig; number of clusters–control: 2.4 ± 1.1 (mean ± SD), median 2, n = 62 AZs, N = 5 mice; PKI: 2.0 ± 1.0, median 2, n = 57 AZs, N = 3 mice; PKI + forskolin: 1.9 ± 1.0, median 2, n = 59 AZs, N = 3 mice; control versus PKI: P = 0.0514, control versus”

• cites [79] Y Hashimotodani, 2017, LTP at hilar mossy cell-dentate granule cell synapses modulates dentate gyrus output by increasing excitation/inhibition balance, Neuron sourceSupported

May combine two claims.

Munc13-1 in synapses appears tightly anchored to the active zone via scaffold proteins and interacts with components of the sub-membranous cytoskeleton, rendering it effectively insoluble.

“Although Munc13s do not have transmembrane domains, Munc13-1 in synapses appears to be tightly anchored to the AZ via scaffold proteins [62,63] and interacts with components of the sub-membranous cytoskeleton [64], rendering it effectively insoluble [65].”

• cites [62] A Betz, 2001, Functional interaction of the active zone proteins Munc13-1 and RIM1 in synaptic vesicle priming, Neuron sourceNot checked — no full text of the source
• cites [63] C Limbach, 2011, Molecular in situ topology of Aczonin/Piccolo and associated proteins at the mammalian neurotransmitter release site, Proc Natl Acad Sci U S A sourceCould not verify

  Citation [65] is attached specifically to the claim that Munc13-1 is effectively insoluble. The Spatial Relationships section describes Munc13’s location and possible movement between the membrane and cytosol, but the passages found by searching for insolubility and detergent extraction do not address whether it is insoluble. (LLM, conf=0.75)

  Experimental — accuracy not yet measured
• cites [64] G Sakaguchi, 1998, A novel brain-specific isoform of β spectrin: isolation and its interaction with Munc13, Biochem Biophys Res Commun sourceNot checked — no full text of the source
• cites [65] N Brose, 1995, Mammalian homologues of Caenorhabditis elegans unc-13 gene define novel family of C2-domain proteins, J Biol Chem sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

Changes in both RRP and Pr have been reported during post-tetanic potentiation (PTP).

“Changes in both RRP and Pr have been also reported during PTP [21].”

• cites [21] D Vandael, 2020, Short-term plasticity at hippocampal mossy fiber synapses is induced by natural activity patterns and associated with vesicle pool engram formation, Neuron sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing).

bMunc13-2 is the second-most abundant isoform expressed at mossy fiber bouton synapses.

“After Munc13-1, the second-most abundant isoform expressed at MFB synapses is bMunc13-2 [40,42,77].”

• cites [40] I Augustin, 1999, Differential expression of two novel Munc13 proteins in rat brain, Biochem J sourcePartly supported

  The Discussion describes Munc13-1 as the most abundant isoform, and the protein-characterization section reports Munc13-2 in synaptic membrane fractions. Neither section identifies bMunc13-2 or ranks isoform abundance at mossy fiber bouton synapses; the localization section measures hippocampal mRNA by region, not protein abundance at those synapses. Page numbers are unavailable in our copy. (LLM, conf=0.84)

  Experimental — accuracy not yet measured
• cites [42] F Varoqueaux, 2002, Total arrest of spontaneous and evoked synaptic transmission but normal synaptogenesis in the absence of Munc13-mediated vesicle priming, Proc Natl Acad Sci U S A sourcePartly supported

  The Discussion (page unavailable) says glutamatergic hippocampal synapses can be differentially equipped with Munc13-1 and Munc13-2. It does not identify the bMunc13-2 splice variant at mossy fiber bouton synapses or rank its abundance there; searches for those terms found no such passage. (LLM, conf=0.82)

  Experimental — accuracy not yet measured
• cites [77] J Breustedt, 2010, Munc13-2 differentially affects hippocampal synaptic transmission and plasticity, Cereb Cortex sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

These might be "superprimed" vesicles.

“These might be “superprimed” vesicles [84,85].”

• cites [84] OM Schlüter, 2006, Rab3 superprimes synaptic vesicles for release: implications for short-term synaptic plasticity, J Neurosci sourceSupported
• cites [85] H Taschenberger, 2016, Superpriming of synaptic vesicles as a common basis for intersynapse variability and modulation of synaptic strength, Proc Natl Acad Sci U S A sourceSupported

May combine two claims.

Baseline activity of cAMP-PKA signaling pathway is important for coupling distance, basal synaptic transmission, and the induction of presynaptic potentiation.

“Moreover, our results revealed that baseline activity of cAMP-PKA signaling pathway is important for coupling distance, basal synaptic transmission, and the induction of presynaptic potentiation, as the application of PKA antagonists led to “uncoupling” of Munc13-1 and CaV2.1 (Figs 5 and S9) and a decrease in synaptic strength [21].”

• cites [21] D Vandael, 2020, Short-term plasticity at hippocampal mossy fiber synapses is induced by natural activity patterns and associated with vesicle pool engram formation, Neuron sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

RIM1/2 recruits Munc13-1s to active zones and interacts with other active zone components to enable exocytosis.

“RIM1/2 recruits Munc13-1s to AZs [72,73] and interacts with other AZ components to enable exocytosis [73–76].”

• cites [72] J Lu, 2006, Structural basis for a Munc13-1 homodimer to Munc13-1/RIM heterodimer switch, PLoS Biol sourcePartly supported

  The Introduction reports that Munc13-1 binds RIM1α/RIM2α at active zones and that disrupting this interaction impairs vesicle priming. Biological Implications describes RIM interactions with Rab3A that may help couple priming to the release machinery. These passages support a role in exocytosis, but do not establish that RIM1/2 recruits Munc13-1 to active zones. (LLM, conf=0.78)

  Experimental — accuracy not yet measured
• cites [73] L Deng, 2011, RIM proteins activate vesicle priming by reversing autoinhibitory homodimerization of Munc13, Neuron sourcePartly supported

  The Introduction says RIMs interact with other active-zone proteins, and the Results show RIM–Munc13 binding relevant to vesicle priming. But the Discussion (Outlook; page unavailable) says the RIM Zn²⁺-finger acts downstream of Munc13 targeting to active zones and cannot physically tether Munc13 there. Thus, this paper does not support the claim that RIM recruits Munc13-1 to active zones. (LLM, conf=0.88)

  Experimental — accuracy not yet measured
• cites [74] PS Kaeser, 2012, RIM genes differentially contribute to organizing presynaptic release sites, Proc Natl Acad Sci U S A sourcePartly supported

  The Abstract says RIMs bind other active-zone components and participate in neurotransmitter release. The Results say RIM1 and RIM2 promote vesicle priming through Munc13, but our copy does not say they recruit Munc13-1 to active zones specifically. (LLM, conf=0.85)

  Experimental — accuracy not yet measured
• cites [75] C Tan, 2022, Rebuilding essential active zone functions within a synapse, Neuron sourceSupported
• cites [76] J Emperador-Melero, 2024, Distinct active zone protein machineries mediate Ca2+ channel clustering and vesicle priming at hippocampal synapses, Nat Neurosci sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing).

Bassoon strongly colocalizes with Munc13-1 but not Munc13-2 at AZs.

“Bassoon, a scaffold protein, is another candidate for phosphorylation, as it strongly colocalizes with Munc13-1 but not Munc13-2 at AZs [60].”

• cites [60] Z Chen, 2013, The Munc13 proteins differentially regulate readily releasable pool dynamics and calcium-dependent recovery at a central synapse, J Neurosci sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Facilitation and PTP may lead to conditional detonation or plasticity-dependent detonation at this synapse.

“Previous work showed that facilitation and PTP may lead to conditional detonation or plasticity-dependent detonation at this synapse [21,51].”

• cites [21] D Vandael, 2020, Short-term plasticity at hippocampal mossy fiber synapses is induced by natural activity patterns and associated with vesicle pool engram formation, Neuron sourcePartly supported

  The Discussion (page unavailable) says mossy fiber plasticity can change transmission modes: increased release probability may enable burst-to-spike transmission, while increased readily releasable pool size could facilitate burst-to-burst transmission. It links the latter pool change to PTP, but does not specifically say that facilitation and PTP produce conditional or plasticity-dependent detonation. (LLM, conf=0.79)

  Experimental — accuracy not yet measured
• cites [51] NP Vyleta, 2016, Plasticity-dependent, full detonation at hippocampal mossy fiber-CA3 pyramidal neuron synapses, Elife sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing).

Several neuromodulators, such as acetylcholine, dopamine, and noradrenaline, have been reported to affect mossy fiber synaptic transmission.

“Several neuromodulators, such as acetylcholine [97], dopamine [98], and noradrenaline [54] have been reported to affect mossy fiber synaptic transmission.”

• cites [97] KE Vogt, 2001, Cholinergic modulation of excitatory synaptic transmission in the CA3 area of the hippocampus, J Neurosci sourceSupported
• cites [98] K Kobayashi, 2007, Dopamine selectively potentiates hippocampal mossy fiber to CA3 synaptic transmission, Neuropharmacology sourceNot checked — no full text of the source
• cites [54] K Kobayashi, 2022, Noradrenaline activation of hippocampal dopamine D1 receptors promotes antidepressant effects, Proc Natl Acad Sci U S A sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing).

PKA is thought to phosphorylate several presynaptic target proteins, including synaptotagmin 12, tomosyn, rabphilins, SNAP 25, and RIMs.

“PKA is thought to phosphorylate several presynaptic target proteins, including synaptotagmin 12, tomosyn, rabphilins, SNAP 25 (synaptosomal-associated protein of 25 kDa), and RIMs [92].”

• cites [92] M Shahoha, 2022, cAMP-dependent synaptic plasticity at the hippocampal mossy fiber terminal., Front Synaptic Neurosci. sourcePartly supported

  The Molecular Mechanisms section identifies synaptotagmin-12, tomosyn-1, rabphilin and RIM1a as PKA targets or putative targets. It describes SNAP-25 as a protein that interacts with rabphilin, but does not say PKA phosphorylates SNAP-25. No page numbers are provided in our copy. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

PKA-dependent phosphorylation of RIM has been shown not to be involved in LTP, but recent evidence highlights the importance of other phosphorylation sites of RIM during plasticity.

“Although PKA-dependent phosphorylation of RIM has been shown not to be involved in LTP [94], recent evidence highlights the importance of other phosphorylation sites of RIM during plasticity [95].”

• cites [94] PS Kaeser, 2008, RIM1alpha phosphorylation at serine-413 by protein kinase A is not required for presynaptic long-term plasticity or learning, Proc Natl Acad Sci U S A sourcePartly supported

  The Results report that removing the PKA phosphorylation site serine-413 from RIM1α did not detectably alter presynaptic long-term plasticity. The Discussion says it is unlikely that RIM1α or RIM2α are direct PKA targets in triggering presynaptic LTP, but this is a qualified conclusion, not a demonstration that PKA-dependent phosphorylation of RIM is uninvolved in all LTP. The clause about other phosphorylation sites carries a different citation and is not attributed to this paper. (LLM, conf=0.85)

  Experimental — accuracy not yet measured
• cites [95] JA Müller, 2022, A presynaptic phosphosignaling hub for lasting homeostatic plasticity, Cell Rep sourceSupported

May combine two claims.

Forskolin changes only the localization of Munc13-1 but not bMunc13-2, which lacks C2A domain and is thought to prime vesicles independently of RIM.

“In this context, it is interesting that forskolin changes only the localization of Munc13-1 but not bMunc13-2, which lacks C2A domain and is thought to prime vesicles independently of RIM [40,96].”

• cites [40] I Augustin, 1999, Differential expression of two novel Munc13 proteins in rat brain, Biochem J sourceCould not verify

  The Introduction describes Munc13-1 translocation in response to diacylglycerol or phorbol ester, and the characterization section reports baseline localization of Munc13 isoforms. Neither addresses a forskolin-induced change, whether bMunc13-2 lacks C2A, or RIM-independent priming; searches for forskolin, C2A, and RIM found no passage establishing those points. Page numbers were not available in our copy. (LLM, conf=0.73)

  Experimental — accuracy not yet measured
• cites [96] H Kawabe, 2017, ELKS1 localizes the synaptic vesicle priming protein bMunc13-2 to a specific subset of active zones, J Cell Biol sourcePartly supported

  The Introduction (page unavailable) describes bMunc13-2 as having a distinct N terminus without the C2A/RIM-binding region and says proteins other than RIMs must be involved in its active-zone targeting and regulation. It does not establish that bMunc13-2 primes vesicles independently of RIM, and a search for forskolin found no passage reporting a differential effect on Munc13-1 and bMunc13-2 localization. (LLM, conf=0.85)

  Experimental — accuracy not yet measured

May combine two claims.

Burst or superburst activity in GCs may lead to detonation, but sparse activation of GCs with neuromodulatory pathways may also efficiently activate the CA3 network.

“Thus, burst or superburst activity in GCs [104] may lead to detonation but sparse activation of GCs in conjunction with activation of neuromodulatory pathways may also efficiently activate the CA3 network.”

• cites [104] X Zhang, 2020, Selective routing of spatial information flow from input to output in hippocampal granule cells, Neuron sourcePartly supported

  The Discussion (§Sparse, Heterogeneous Activity of Identified GCs; page unavailable) mentions bursts of granule-cell spikes, and §Role of Sparsely and Heterogeneously Active GCs in the Dentate Gyrus Network proposes neuromodulator-mediated recruitment of granule cells. But the copy does not describe superbursts or establish that bursts cause detonation or that neuromodulation efficiently activates the CA3 network. (LLM, conf=0.82)

  Experimental — accuracy not yet measured

The quote only partly states this claim.

Forskolin increases the number of docked synaptic vesicles per 100 nm of active zone profile length.

“After forskolin application, the number of docked SVs increased in comparison to control conditions”

May combine two claims.

Under control conditions, the NND between Munc13-1/2 and Ca2+ channel clusters was 97.4 and 79.1 nm, and the mean WPD was 51.2 and 40.3 nm.

“Under control conditions, we found that the NND between Munc13-1/2 and Ca2+ channel clusters was 97.4 and 79.1 nm, whereas the mean WPD was 51.2 and 40.3 nm.”

May combine two claims.

Chemical potentiation caused a significant reorganization of the coupling configuration, including a slight reduction in NND and WPD between presynaptic Ca2+ channels and Munc13-1.

“Furthermore, we found a significant reorganization of the coupling configuration, including a slight reduction in NND and WPD between presynaptic Ca2+ channels and Munc13-1 (i.e., structural coupling).”

• Also stated in: § Changes in coupling topography during chemical potentiation · plain

  “In contrast, forskolin significantly altered the coupling configuration between Ca2+ channels and primed vesicles.”

May combine two claims.

Forskolin increases Pr, although the effects are smaller than those on the vesicular pool.

“Our biophysical analysis reveals that forskolin increases Pr, although the effects are smaller than those on the vesicular pool.”

May combine two claims.

The number of RIM1/2 and Munc13 clusters per AZ are comparable and are increased by forskolin to roughly the same extent.

“Consistent with this hypothesis, the number of RIM1/2 and Munc13 clusters per AZ are comparable and are increased by forskolin to roughly the same extent (S4 Table).”

May combine two claims. The quote only partly states this claim.

Chemical potentiation/forskolin increased the readily releasable pool (RRP) by 146% (to 246% of control) and increased release probability (Pr) by 49%.

“Functional analysis revealed that chemical potentiation increased both RRP and Pr, by 146% and 49%, respectively.”

• Also stated in: § Increase in RRP and docked vesicle pool size · plain

  “Functional analysis shows that forskolin increases the size of the RRP by 146%, i.e., to 246% of control value.”

May combine two claims.

The increase in the number of docked vesicles is smaller, and the increase in the number of Munc13 clusters is much smaller than the increase in the RRP.

“A potential caveat is that the increase in the number of docked vesicles is smaller, and the increase in the number of Munc13 clusters is much smaller than the increase in the RRP.”

May combine two claims.

The RRP size (1.6 per AZ) is an order of magnitude smaller than the number of docked vesicles (13.0 per AZ) and less than the total number of Munc13-1/bMunc13-2 clusters (approximately 4.2).

“This is an order of magnitude smaller than the number of docked vesicles (13.0 per AZ; S4 Table) and also less than the total number of Munc13-1/bMunc13-2 clusters (approximately 4.2).”

May combine two claims.

This RRP increase correlates with an increased number of docked vesicles (to 21.0 per AZ) and Munc13 clusters (to 4.8 per AZ).

“This correlates with an increased number of docked vesicles (to 21.0 per AZ) and in the number of Munc13 clusters (to 4.8 per AZ; S4 Table).”

May combine two claims.

Chemical potentiation increased the number of vesicles and the number of Munc13-1 clusters near the plasma membrane.

“Structural analysis demonstrated that chemical potentiation increased the number of vesicles and the number of clusters of the priming protein Munc13-1 near the plasma membrane”

May combine two claims.

In control condition, temperature did not affect EPSC1 amplitude and RRP size but did affect Pr and refilling rate.

“In control condition, temperature did not affect EPSC1 amplitude (24°C: 154.1 ± 15.1 pA (mean ± SEM), median 146.8 pA, n = 8 cells, N = 8 rats here and below; 32°C: 437.7 ± 130.7 pA, median 465.5 pA, n = 7 cells, N = 6 rats here and below; 24°C versus 32°C: P = 0.3969, Mann–Whitney test) and RRP size (24°C: 1.16 ± 0.21 nA (mean ± SEM), median 1.27 nA; 32°C: 1.33 ± 0.49 nA (mean ± SEM), median 0.83”

May combine two claims.

The effects of forskolin on both the RRP and the primed vesicles are blocked by both H-89 and PKI 14-22, indicating an involvement of PKA.

“The effects of forskolin on both the RRP and the primed vesicles are blocked by both H-89 and PKI 14–22, indicating an involvement of PKA.”

May combine two claims.

Forskolin and isoproterenol both potentiate mossy fiber synaptic transmission, but isoproterenol's action appears mechanistically distinct and more variable.

“Our results indicate that not only the AC activator forskolin potentiates mossy fiber synaptic transmission. In addition, the more natural agonist isoproterenol shows this effect, although its action appears to be mechanistically distinct and more variable (Fig 2).”

May combine two claims.

Forskolin shortened the distances between Munc13-1 and CaV2.1, but did not have the same effect on WPDs between RIM1/2 and CaV2.1.

“Although forskolin shortened the distances between Munc13-1 and CaV2.1, we did not observe the same effect on WPDs between RIM1/2 and CaV2.1.”

May combine two claims.

Natural activation of the cAMP-PKA signaling pathway leads to expansion of the RRP, with subtle differences and larger variability than direct AC activation by forskolin.

“These results indicate that natural activation of the cAMP-PKA signaling pathway leads to expansion of the RRP, although with subtle differences and larger variability than direct AC activation by forskolin.”

Probably not a substantial claim: may not pass S2 (checkable).

The connection between synaptic biophysics and morphology remains unclear.

“However, the connection between synaptic biophysics and morphology remains unclear.”

May combine two claims.

The cumulative EPSC method can distinguish between changes in RRP and Pr, although the resulting RRP values represent pool decrement rather than absolute pool size.

“This method can distinguish between changes in RRP and Pr, although the resulting RRP values represent “pool decrement” rather than absolute pool size ([11]; see Materials and methods).”

• cites [11] E. Neher, 2015, Merits and limitations of vesicle pool models in view of heterogeneous populations of synaptic vesicles, Neuron sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

Biophysical analysis often determines the number of functional release sites, but the structural correlates have not been identified.

“For example, biophysical analysis often determines the number of functional release sites, but the structural correlates have not been identified [6].”

• cites [6] S Holler, 2021, Structure and function of a neocortical synapse, Nature sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S2 (checkable).

The hippocampal mossy fiber-CA3 pyramidal neuron synapse is an ideal synapse to tackle these questions.

“The hippocampal mossy fiber–CA3 pyramidal neuron (PN) synapse, formed between dentate gyrus granule cells (GCs) and CA3 PNs, is an ideal synapse to tackle these questions [24,25].”

• cites [24] RA Nicoll, 2005, Synaptic plasticity at hippocampal mossy fibre synapses., Nat Rev Neurosci sourceNot checked — no full text of the source
• cites [25] D Vandael, 2024, Structure, biophysics, and circuit function of a "giant" cortical presynaptic terminal., Science sourceNot checked — no full text of the source

May combine two claims.

The effects of forskolin on localization of Munc13 isoforms are differential, with a selective increase of Munc13-1 but not bMunc13-2 clusters.

“These results indicate that the effects of forskolin on localization of Munc13 isoforms were differential, associated with a selective increase of Munc13-1 but not bMunc13-2 clusters.”

Classified as probably not a substantial claim.

Forskolin, an adenylyl cyclase activator, leads to marked chemical potentiation.

“Similarly, forskolin, an adenylyl cyclase (AC) activator, leads to marked chemical potentiation [29,32,33].”

• cites [29] MG Weisskopf, 1994, Mediation of hippocampal mossy fiber long-term potentiation by cyclic AMP, Science sourceNot checked — no full text of the source
• cites [32] G Maccaferri, 1998, Target-specific expression of presynaptic mossy fiber plasticity, Science sourceNot checked — no full text of the source
• cites [33] M Midorikawa, 2017, Kinetics of releasable synaptic vesicles and their plastic changes at hippocampal mossy fiber synapses, Neuron sourceNot checked — no full text of the source

May combine two claims.

The forskolin-induced changes in Munc13-1's spatial distribution are largely PKA-dependent, implying PKA-mediated changes in vesicle priming.

“These results indicate that the forskolin-induced changes in Munc13-1’s spatial distribution are largely PKA-dependent, implying PKA-mediated changes in vesicle priming.”

May combine two claims.

The long depolarizing pulse may trigger the release of tethered vesicles or activate fast refilling of vesicles from the recycling or reserve pool.

“Thus, the long depolarizing pulse may trigger the release of tethered vesicles or, in addition, activate fast refilling of vesicles from the recycling or reserve pool [9,10].”

• cites [9] SO Rizzoli, 2005, Synaptic vesicle pools., Nat Rev Neurosci sourceNot checked — no full text of the source
• cites [10] AA Alabi, 2012 sourceNot checked — no full text of the source

May combine two claims.

This is consistent with the existence of "superprimed" vesicles, although the fraction of these vesicles may increase (to 3.8/4.8 = 79%).

“This is again consistent with the existence of “superprimed” vesicles, although the fraction of these vesicles may increase (to 3.8/4.8 = 79%).”

May combine two claims.

The cAMP-PKA pathway can bidirectionally regulate the vesicle-channel topography at mossy fiber terminals, resulting in changes in Pr.

“Our results give the first direct evidence that the cAMP-PKA pathway can bidirectionally regulate the vesicle-channel topography at mossy fiber terminals, resulting in changes in Pr.”

May combine two claims.

This number is larger than that of primed vesicles and even exceeds that of docked vesicles.

“This number is larger than that of primed vesicles and even exceeds that of docked vesicles.”

May combine two claims.

Only a fraction of docked vesicles seems to be primed and only a fraction of those is fusion-competent (1.6/4.2 = 38%).

“Thus, only a fraction of the docked vesicles seems to be primed and only a fraction of those is fusion-competent (1.6/4.2 = 38%).”

May combine two claims.

Because forskolin-induced potentiation occludes with LTP, short-term and long-term plasticity converge on similar pool mechanisms.

“As forskolin-induced potentiation occludes with LTP at this synapse [29], this suggests that both short-term and long-term plasticity converge on similar pool mechanisms.”

• cites [29] MG Weisskopf, 1994, Mediation of hippocampal mossy fiber long-term potentiation by cyclic AMP, Science sourceNot checked — no full text of the source

May combine two claims.

Capacitance measurements from hippocampal mossy fiber terminals suggest that long depolarizing pulses release approximately 500-1,400 vesicles, corresponding to 17 to 48 vesicles per AZ.

“Capacitance measurements from hippocampal mossy fiber terminals suggest that long depolarizing pulses release approximately 500–1,400 vesicles, corresponding to 17 to 48 vesicles per AZ [33,86].”

• cites [33] M Midorikawa, 2017, Kinetics of releasable synaptic vesicles and their plastic changes at hippocampal mossy fiber synapses, Neuron sourceNot checked — no full text of the source
• cites [86] S Hallermann, 2003, A large pool of releasable vesicles in a cortical glutamatergic synapse, Proc Natl Acad Sci U S A sourceNot checked — no full text of the source

May combine two claims.

Isoproterenol has effects comparable to forskolin, suggesting that beta 1/2 adrenoreceptors and GS proteins activate the same pathway more physiologically.

“Moreover, isoproterenol has effects comparable to forskolin, suggesting that beta 1/2 adrenoreceptors and GS proteins activate the same pathway more physiologically.”

Classified as probably not a substantial claim.

All EM micrographs from ultrathin sections were analyzed blindly toward the condition of treatment.

“All EM micrographs from ultrathin sections were analyzed blindly toward the condition of treatment; an identification number (IN) was assigned to each sample during HPF that was changed during FS or FRL.”

Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing). May combine two claims.

Noradrenaline release from locus coeruleus neurons may signal arousal, novelty, and reward prediction.

“It has been suggested that noradrenaline release from locus coeruleus neurons may signal arousal, novelty, and reward prediction [109].”

• cites [109] SJ Sara, 2009, The locus coeruleus and noradrenergic modulation of cognition., Nat Rev Neurosci sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

The stratum lucidum is the region with the highest density of innervation by neuromodulatory inputs.

“Within the hippocampus, the stratum lucidum (the region of mossy fiber termination) is the region with the highest density of innervation by neuromodulatory inputs, such as noradrenaline, adrenaline, and dopamine [99,100].”

• cites [99] R Loy, 1980, Noradrenergic innervation of the adult rat hippocampal formation, J Comp Neurol sourceNot checked — no full text of the source
• cites [100] AM Moudy, 1993, Development of dopamine-beta hydroxylase–positive fiber innervation of the rat hippocampus, Synapse sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

RRP estimates obtained by the cumulative EPSC peak amplitude method represent pool decrement rather than absolute pool size.

“Note that the RRP estimates by this method represent “pool decrement” rather than absolute pool size [11].”

• cites [11] E. Neher, 2015, Merits and limitations of vesicle pool models in view of heterogeneous populations of synaptic vesicles, Neuron sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

All procedures complied with institutional, Austrian, and European ethical regulations and were approved by the Bundesministerium für Bildung, Wissenschaft und Forschung of Austria.

“All procedures strictly complied with institutional, Austrian, and European ethical regulations for animal experiments, and were approved by the Bundesministerium für Bildung, Wissenschaft und Forschung of Austria (Reference number 2020–0.648.587 and 2022–0121.440).”

Probably not a substantial claim: may not pass S3 (load-bearing).

Phosphorylation of RIMs may change binding of Munc13 and thereby priming of SVs.

“Thus, the phosphorylation of RIMs may change binding of Munc13 and thereby priming of SVs.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The heterogeneous expression of beta-adrenergic receptors, lower cAMP production, and parallel activation of Gs alpha and beta-gamma pathways may explain the variability of isoproterenol's action.

“The heterogeneous expression of beta-adrenergic receptors on mossy fiber terminals, the lower level of cAMP production, and the parallel activation of Gs alpha and beta-gamma pathways by the natural agonist may explain the variability.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Identification numbers were randomized during sectioning, imaging, and analysis.

“Finally, INs were randomized during sectioning, imaging, and analysis.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Phosphorylation of SNAP 25 protein by PKA affected the size of the releasable pool in chromaffin cells.

“For example, phosphorylation of SNAP 25 protein by PKA affected the size of the releasable pool in chromaffin cells [93].”

• cites [93] G Nagy, 2004, Regulation of releasable vesicle pool sizes by protein kinase A-dependent phosphorylation of SNAP-25, Neuron sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

Batches of secondary antibodies showed a clear separation between 5-nm and 10-nm particle populations.

“Batches of secondary antibodies were tested and distribution of the particle sizes showed a clear separation between 2 populations (mean size of 5-nm antibody: (mean ± SEM) 5.07 ± 0.07 nm; 10-nm antibody: 10.12 ± 0.08 nm).”

Classified as probably not a substantial claim.

Only recordings with <15 MΩ postsynaptic series resistance and stationary postsynaptic responses were included for analysis.

“Only recordings with <15 MΩ postsynaptic series resistance and stationary postsynaptic responses (EPSC1; based on Pearson correlation coefficient; P > 0.05) were included for analysis.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Munc13-1 may selectively translocate to the protein network of the AZ.

“This may suggest that Munc13-1 selectively translocates to the protein network of the AZ.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Membrane potentials are given without correction for liquid junction potentials.

“Membrane potentials are given without correction for liquid junction potentials.”

May combine two claims.

Chemical potentiation at hippocampal mossy fiber synapses is associated with complex changes in both vesicle pool organization and coupling configuration.

“Altogether, our results suggest that chemical potentiation at hippocampal mossy fiber synapses is associated with complex changes in both vesicle pool organization and coupling configuration.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Most ε values were in the range of mean ± 2 SD of NND.

“Most ε values were in the range of mean ± 2 SD of NND.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Neuromodulators can change the induction rules and time course of mossy fiber plasticity.

“Moreover, neuromodulators can change the induction rules and time course of mossy fiber plasticity [101,102].”

• cites [101] WF Hopkins, 1988, Noradrenergic enhancement of long-term potentiation at mossy fiber synapses in the hippocampus, J Neurophysiol sourceNot checked — no full text of the source
• cites [102] YY Huang, 1996, Modulation of both the early and the late phase of mossy fiber LTP by the activation of beta-adrenergic receptors, Neuron sourceNot checked — no full text of the source