Adolescent nicotine exposure transiently increases high-affinity nicotinic receptors and modulates inhibitory synaptic transmission in rat medial prefrontal cortex

May combine two claims.

The acute nicotine effect was much larger in adults than in adolescents, which does not explain the increased sensitivity of adolescents to nicotine.

“In addition, the acute nicotine effect was much larger in adults than in adolescents, thereby not explaining the increased sensitivity of adolescents for nicotine (25, 45).”

• cites [25] sourcePartly supported

  The Discussion (page unavailable) reports that, in a cited in vivo study, an acute nicotine challenge increased extracellular striatal dopamine in adult rats but produced no significant increase in adolescents. That supports an age difference in this specific response, not a general claim that the acute nicotine effect was much larger in adults. The paper does not draw the stated conclusion that this difference fails to explain adolescents’ increased nicotine sensitivity. (LLM, conf=0.83)

  Experimental — accuracy not yet measured
• cites [45] sourceDisputed

  The Results (section 3; page unavailable) report an approximately twofold larger nicotine-induced preference response in adolescent than adult rats, the opposite of the claimed age comparison. The Introduction (section 1; page unavailable) also reports that a single nicotine injection produced conditioned place preference in adolescents but not adults. The paper does not conclude that a larger acute effect in adults fails to explain adolescent sensitivity. (LLM, conf=0.86)

  Checked by a reasoning model — may be wrong.

  Experimental — accuracy not yet measured

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

Antibody specificity was verified by quantitative immunoprecipitation or immunopurification using nAChRs from various CNS areas of wild-type and null mutant mice, which allowed selection of subunit-specific antibodies.

“Antibody specificity was checked by means of quantitative immunoprecipitation or immunopurification experiments using nAChRs from different areas of the CNS of wild-type α4, α5, α6, β2, β3, and β4 (+/+) and null mutant (−/−) mice, which allowed selection of antibodies specific for the subunit of interest, and assessing the immunoprecipitation capacity of each antibody.”

• cites [29] sourceSupported

Classified as probably not a substantial claim.

Earlier studies show that adolescent nicotine exposure causes acute and longer-lasting changes in nAChR binding and function in regions such as cortex and striatum.

“Previous studies have shown that adolescent nicotine exposure leads to acute and longer-lasting changes in nAChR binding (25, 26) and function (20) in brain regions such as cortex and striatum.”

• cites [25] sourceSupported
• cites [26] sourceNot checked — no full text of the source
• cites [20] sourceNot checked — no full text of the source

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

Doura et al. found that adult nicotine exposure causes a larger up-regulation of nAChRs in the PFC and most of the brain than adolescent nicotine exposure.

“Previously Doura et al. (25) found that adult nicotine exposure causes a larger up-regulation of nAChRs in the PFC and most of the brain than adolescent nicotine exposure.”

• cites [25] sourcePartly supported

  The Results report larger nicotine-induced increases in adult than periadolescent rats in 35 of 38 regions measured for α4β2⁎ receptors; the frontal-cortex entries also show larger adult increases. But the claim generalizes this pattern to nAChRs as a whole: the Discussion says α6⁎ receptor down-regulation was greater in periadolescents. The paper reports frontal-cortex measurements rather than explicitly identifying them as PFC (Results and Discussion; page unavailable). (LLM, conf=0.86)

  Experimental — accuracy not yet measured

May combine two claims.

Nicotine in mPFC changes the rules for spike-timing-dependent plasticity and thereby prevents synaptic potentiation.

“In addition, nicotine in the mPFC changes the rules for spike-timing-dependent plasticity and thereby prevents synaptic potentiation (34).”

• cites [34] sourcePartly supported

  The Results section reports that nicotine prevented potentiation when presynaptic input was paired with a single postsynaptic action potential, and the Discussion says nicotine raises the threshold for spike-timing-dependent plasticity. But the paper also reports that stronger postsynaptic activity can partially restore potentiation, so nicotine does not prevent it categorically. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

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

α4 immunostaining in mouse hippocampus shows that α4 expression decreases with age from young adults to very old mice.

“This has also been shown by means of α4 immunostaining of mouse hippocampus, in which expression of α4 decreases with age from young adults (2–4 mo of age) to very old mice (24–28 mo of age) (40).”

• cites [40] sourcePartly supported

  The Results section (“Anti-α4 immunoreactivity in the brain of young and aged CBA/J mice”; page unavailable) reports substantially fewer hippocampal α4-immunopositive neurons in aged mice, supporting the main finding. However, its young mice were 3–5 months old, not the cited sentence’s 2–4 months; the aged group was 24–28 months old. (LLM, conf=0.90)

  Experimental — accuracy not yet measured

May combine two claims.

There is no developmental decline in α4 and β2 mRNA levels in cortex, but binding studies show α4β2 expression is higher in adolescents than adults.

“Although there is no developmental decline in α4 and β2 mRNA levels in the cortex, binding studies have shown that α4β2 expression is higher in adolescents than in adults (25).”

• cites [25] sourcePartly supported

  The Results (page unavailable) report higher α4β2⁎ binding in saline-treated periadolescent rats than in adults across the measured brain regions. The paper used binding autoradiography; our copy does not establish the claimed absence of a developmental decline in cortical α4 and β2 mRNA levels (searched: mRNA and developmental decline). (LLM, conf=0.87)

  Experimental — accuracy not yet measured

May combine two claims.

Different types of PFC interneurons express both α7 and α4β2-containing nAChRs on their cell bodies, and nAChR stimulation increases GABAergic transmission.

“In addition, different types of PFC interneurons in the mPFC express both α7 and α4β2-containing nAChRs on their cell bodies (34), and nAChR stimulation increases GABAergic transmission (34).”

• cites [34] sourceSupported

May combine two claims.

At a system level, this might contribute to differences in acute rewarding effects of nicotine and might underlie increased sensitivity of adolescents.

“At a system level, this might contribute to differences in the acute rewarding effects of nicotine, and might underlie the increased sensitivity of adolescents (5, 51).”

• cites [5] sourceSupported
• cites [51] sourceSupported

May combine two claims.

The majority of interneurons express nAChRs composed of α4β2*, although they also express other subunits.

“the majority of interneurons express nAChRs that are composed of α4β2*, although they also express other subunits (34)”

• cites [34] sourcePartly supported

  In “Different Types of Interneurons Differentially Express mRNA for nAChRs” (Table 1), the paper reports α4 expression in the largest number of LTS and RSNP cells, with β2 and α7 mRNA also found in those cell types. It also reports hardly any nAChR-subunit mRNA in FS cells. These findings support expression of several subunits in some interneuron types, but do not establish that a majority of interneurons express assembled α4β2* receptors. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

May combine two claims.

Nicotinic receptors in mPFC are localized presynaptically on glutamatergic and dopaminergic terminals, where they mediate glutamate and dopamine release, respectively.

“Nicotinic receptors in the mPFC are localized presynaptically on glutamatergic and dopaminergic terminals, where they mediate glutamate (35, 48) and dopamine (49) release, respectively.”

• cites [35] sourceNot checked — no full text of the source
• cites [48] sourceSupported
• cites [49] sourceNot checked — no full text of the source

May combine two claims.

The difference in regulation of nAChRs may reflect different timing of maturation of these areas, as shown by proteomics comparing mPFC and motor cortex and by human brain imaging studies.

“The difference in regulation of nAChRs may reflect the different timing of maturation of these areas, as previously shown using proteomics experiments comparing mPFC and motorcortex (39), and for human brain development using imaging studies (27).”

• cites [39] sourceNot checked — no full text of the source
• cites [27] sourceSupported

May combine two claims.

The nAChR increase after adolescent nicotine exposure is temporary and absent five weeks after exposure in either adolescent or adult rats.

“This increase was transient and was not observed 5 wk following either adolescent or adult nicotine exposure.”

May combine two claims.

Post hoc analysis of the age × time-point interaction found no significant differences between groups at the two time points during treatment; only a trend toward higher plasma levels appeared at the first time point.

“Post hoc analysis of the effect of age × time point (F [2,42]=3.52, P=0.039) does not reveal significant differences between groups at the 2 time points during treatment regimen; only for the first time point a trend (P=0.064 adolescent vs. adult at N1.1) toward higher plasma levels was observed.”

May combine two claims.

For circulating cotinine, there was no age effect, but a clear time-point effect.

“However, for circulating levels of cotinine (the major metabolite of nicotine) there was no age effect (Fig. 1B; age F [1,42]=1.43, ns), but only a clear effect of time point (F [2,42]=155.24, P<0.001).”

• AssumptionRests on an assumption: Cotinine has a longer half-life than nicotine.

May combine two claims.

The inhibitory synaptic transmission effects are temporary and specific, occurring only shortly after adolescent nicotine exposure, not after five weeks, and not in adult-exposed animals.

“These effects were transient and specific, and observed only acutely after adolescent nicotine exposure, but not after 5 wk, and no changes were observed in adult-exposed animals.”

May combine two claims.

When mPFC and occipital cortex were analyzed separately, only mPFC showed effects of age and time and trends for treatment and age×time×treatment interaction.

“When these 2 cortical regions were analyzed separately, only the mPFC showed an effect of age (F [1,47]=23.07, P<0.001) and time (F [1,47]=21.72, P<0.001) and a trend for treatment (F [1,47]=2.77, P=0.10) and interaction age × time × treatment (F [1,47]=3.32, P=0.075).”

May combine two claims.

Per-region analysis of 125I-αBgt binding revealed only an age effect in mPFC and a trend for time in occipital cortex, with no treatment effect or interactions.

“Despite this, further analysis per region revealed only an age effect in the mPFC (F [1,24]=22,49, P<0.001) and a trend for time (F [1,26]=4.17, P=0.051) in the occipital cortex, but again no effect of treatment and no interactions.”

May combine two claims.

In rat mPFC, 3H-Epi binding to high-affinity nAChRs decreased almost linearly from P34 to P104, while occipital cortex showed no such decrease.

“Between P34 and P104, there was an almost linear decrease in nAChR levels (3H-Epi binding) in the mPFC (Supplemental Fig. S1; age, P<0.001), but not in the occipital cortex (age, n.s.).”

May combine two claims.

The nicotine-induced increase in α4- and β2-containing nAChRs was absent in adult animals and long after nicotine exposure.

“We confirmed that this effect was absent in adult animals, and long after nicotine exposure (Table 2).”

May combine two claims.

In mPFC, nicotine treatment increased 3H-Epi binding in adolescent but not adult animals at 1 day after injections, with no effect of saline, and this increase was not present 5 weeks later.

“In summary, in the mPFC, the effect of age was apparent with increased 3H-Epi binding due to nicotine treatment, in the absence of an effect due to saline, only 1 d (nicotine adolescent vs. nicotine adult, P<0.001; adolescent nicotine vs. saline, P<0.001), but not 5 wk, following nicotine injections (Fig. 2A).”

May combine two claims.

In the nicotine treatment paradigm, 125I-αBgt binding showed effects of age, region, and time, but no treatment effect and no four-way interaction.

“In addition, for the nicotine treatment paradigm using a 4-factorial ANOVA, we found an effect of age (F [1,50]=7.07, P=0.029), region (F [1,50]=11.12, P=0.002), and time (F [1,50]=4.37, P=0.042), but no treatment effect and no 4-way interaction (P=0.583).”

May combine two claims.

In occipital cortex, only a time effect and a trend for age were found, with no treatment effect or interaction.

“In the occipital cortex, there was only an effect of time (F [1,37]=10.81, P=0.002), and a trend for age (F [1,37]=2.87, P=0.10), but no effect of treatment and no interaction (P=0.43 and 0.21, respectively; Table 1).”

May combine two claims.

Nicotine increased frequency and amplitude of sIPSCs in layer II/III pyramidal neurons of mPFC.

“Nicotine increased frequency (P<0.001; nicotine peak=528.9±76%, baseline=101.9±2.5%) and amplitudes (P=0.003; nicotine peak=126.8±8.1%, baseline=99.9±1.5%) of sIPSCs measured in pyramidal neurons in layer II/III (Fig. 3A–D).”

May combine two claims.

In mPFC, only α4- and β2-containing nAChRs, but not α5-containing ones, showed a significant increase in expression due to nicotine in adolescent animals (α4 P=0.018; β2 P=0.030).

“Only for the α4 and β2 subunits, but not other subunits, such as α5, did we find a significant increase in expression due to nicotine (α4-containing nAChRs, adolescent nicotine vs. saline, P=0.018; β2-containing nAChRs, adolescent nicotine vs. saline, P=0.030; Fig. 2B).”

May combine two claims.

In combined mPFC and occipital cortex analysis, 3H-Epi binding was affected by age, time after nicotine exposure, and a four-way interaction of treatment, age, time, and region, with trends for treatment and region.

“we observed altered 3H-Epi-binding as an effect of age of treatment (age, F [1,84]=6.34, P=0.014), time after nicotine exposure (time, F [1,84]=30.54, P<0.001), a 4-way interaction of treatment × age × time × region (F [1,84]=4.63, P=0.034), and a trend for treatment (F [1,84]=3.042, P=0.085) and region (F [1,84]=2.93, P=0.091).”

May combine two claims.

Nicotine had a greater effect on sIPSC amplitude in nicotine-treated animals than in saline-treated animals and shifted the cumulative distribution to larger events.

“Nicotine had a greater effect on sIPSC amplitude (P=0.026; nicotine effect in nicotine-treated animals=170.0±18.1%; nicotine effect in saline-treated animals=126.8±8.1%) and shifted the cumulative distribution to larger events (Fig. 3E, F; K-S test, Z=1.5, P=0.02).”

Probably not a substantial claim: may not pass S4 (based).

Nicotine has no effect on glutamatergic spontaneous transmission onto layer II/III pyramidal neurons.

“nicotine has no effect on glutamatergic spontaneous transmission onto layer II/III pyramidal neurons (unpublished data)”

May combine two claims.

Neither adolescent nor adult nicotine exposure has long-term effects on nAChR expression.

“Despite its acute effects, our data showed that neither adolescent nor adult nicotine exposure have long-term effects on the expression of nAChRs, in accordance with findings of others (46).”

• cites [46] sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

Between injections, nicotine is entirely cleared from plasma, leading to repeated activation of nAChRs.

“Moreover, between injections, nicotine is entirely cleared from the plasma, thus leading to repeated activation of nAChRs.”

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

Different nAChR subtypes are expressed in substantially different brain regions.

“The different receptor subtypes show substantial brain-region-specific expression (9).”

• cites [9] sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

To prevent α7-containing receptor subtypes from contributing to 3H-Epi binding, the binding was done in the presence of 2 μM 125I-αBgt.

“To ensure that the α7-containing receptor subtypes did not contribute to 3H-Epi (specific activity 50–66 Ci/mmol; GE Healthcare, Little Chalfont, UK) binding to solubilized receptors (30), the binding in the extract and immunoprecipitation experiments was performed in the presence of 2 μM 125I-αBgt, which specifically binds to α7*-nAChRs (and thus prevents 3H-Epi binding to these sites).”

• cites [30] sourceNot checked — no full text of the source

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

Eleven nAChR subunits have been identified in mammals, divided into eight α and three β subunits.

“Eleven nAChR subunits have so far been identified in mammals and are classified into 8 α and 3 β subunits (8).”

• cites [8] sourceNot checked — no full text of the source

May combine two claims.

Adolescent animals are more sensitive to nicotine-conditioned place preference than adults and show it at lower nicotine doses.

“Furthermore, adolescent animals are more sensitive to nicotine-conditioned place preference than adults and show this at lower nicotine doses (20–24).”

• cites [20] sourceNot checked — no full text of the source
• cites [21] sourceNot checked — no full text of the source
• cites [22] sourceNot checked — no full text of the source
• cites [23] sourceNot checked — no full text of the source
• cites [24] sourceNot checked — no full text of the source

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

High-dose chronic and intermittent nicotine exposure raises high-affinity nicotinic receptor levels in adult humans and rodents.

“It has been shown that high-dose chronic and intermittent nicotine exposure increases levels of high-affinity nicotinic receptors in adult humans and rodents (10–14).”

• cites [10] sourceNot checked — no full text of the source
• cites [11] sourceNot checked — no full text of the source
• cites [12] sourceNot checked — no full text of the source
• cites [13] sourceNot checked — no full text of the source
• cites [14] sourceNot checked — no full text of the source

May combine two claims.

The increase in sIPSC frequency reflects a larger number of spontaneous spikes, while the rise in sIPSC amplitude probably reflects a larger number of simultaneously occurring events.

“The increase in sIPSC frequency reflects a larger number of spontaneous spikes, whereas the rise in sIPSC amplitude probably reflects a larger number of simultaneously occurring events.”

May combine two claims.

The lack of effect on sIPSC frequency is probably due to a saturating effect of nicotine on sIPSC frequency, so further increases in firing can only lead to more simultaneous events (higher sIPSC amplitude).

“This is probably due to an already saturating effect of nicotine on sIPSC frequency (in some cases >10-fold increase) so that further increase in firing can only lead to more simultaneous events (higher sIPSC amplitude).”

May combine two claims.

The increase in α4β2-containing nAChRs at 1 day, but not 5 weeks, after adolescent nicotine exposure is paralleled by increased interneuron sensitivity to nicotine and leads to increased nicotine-induced firing in mPFC inhibitory circuitry.

“The increase in α4β2-containing nAChRs at 1 d, but not 5 wk, after nicotine exposure during adolescence (but not adulthood) is therefore paralleled by increased interneuron sensitivity to nicotine and leads to increased nicotine-induced firing in the inhibitory circuitry of the mPFC.”

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

α7-type nAChRs are less susceptible to regulation, perhaps due to their relatively low affinity for nicotine.

“However, α7-type nAChRs are less prone to regulation, possibly because of their relative low affinity for nicotine (15).”

• cites [15] sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

Rats aged about 25-50 days (P25-50) show similar behavioral and developmental changes.

“Similar behavioral and developmental changes occur in rats aged ~25–50 d [postnatal day (P) 25–50; ref. 7].”

• cites [7] sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

Synaptic pruning and myelination are believed to continue until about age 20 in humans.

“Processes such as synaptic pruning and myelination are thought to continue until approximately the age of 20 in humans (6).”

• cites [6] sourceNot checked — no full text of the source

May combine two claims.

These receptors contribute to the acute rewarding effects of nicotine and may explain adolescents' greater sensitivity to nicotine.

“Together, this suggests that these receptors play a role in mediating the acute rewarding effects of nicotine and may underlie the increased sensitivity of adolescents to nicotine.”

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

Nonspecific binding was measured in parallel samples containing 100 nM unlabeled epibatidine.

“Nonspecific binding (on average 5–10% of total binding) was determined in parallel samples containing 100 nM unlabeled epibatidine.”

May combine two claims.

Lower plasma nicotine levels in adolescent rats on the first day of nicotine exposure may be due to faster nicotine metabolism, because their plasma cotinine levels on the first day were slightly higher.

“The lower plasma nicotine levels observed in adolescent rats on the first day of nicotine exposure may be due to faster nicotine metabolism, because their plasma levels of cotinine (the active metabolite of nicotine) on the first day were slightly higher.”

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

The lower plasma cotinine levels in adolescents could cause known differences in positive and negative effects of nicotine between adolescents and adults.

“This could be the cause of known differences in positive and negative effects of nicotine in adolescents compared with adults.”

May combine two claims.

sIPSCs are used as a proxy to determine numbers of functional nAChRs and most likely represent only a fraction of the total nAChRs in mPFC.

“Thus, sIPSCs are used as a proxy to determine numbers of functional nAChRs, and most likely represent only a fraction of the total number of nAChRs in the mPFC.”

May combine two claims.

The up-regulation of nicotinic receptors depends on age and brain region.

“Our data showed that the up-regulation of nicotinic receptors depends on age and brain region.”

May combine two claims.

Up-regulated 3H-cystine binding, representing mainly α4β2* receptors, was found in cerebral cortex of both adult and adolescent rats 2-3 days after last exposure to nicotine using an osmotic minipump, although plasma nicotine levels were not reported.

“Up-regulated 3H-cystine binding, representing mainly a4b2* receptors, was found in the cerebral cortex of both adult (46) and adolescent (44) rats 2–3 d after the last exposure to nicotine using an osmotic minipump, although plasma nicotine levels were not reported.”

• cites [46] sourceNot checked — no full text of the source
• cites [44] sourceNot checked — no full text of the source

May combine two claims.

Since TTX completely blocks the effect of nicotine on sIPSCs, nAChRs must be located either on somas of interneurons or on axons of GABAergic projections to PFC.

“since TTX completely blocks the effect of nicotine on sIPSCs, nAChRs must be located either on somas of interneurons or on the axons of GABAergic projections to PFC”

Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing). May combine two claims.

The enhanced short-term up-regulation of high-affinity nAChRs in adolescent mPFC may have functional consequences and may be the first step in a cascade leading to long-term adaptation of neuronal circuitry or other systemic effects.

“However, the enhanced short-term up-regulation of high-affinity nAChRs in adolescent mPFC may have functional consequences and perhaps be the first step in a cascade of events leading to long-term adaptation of neuronal circuitry or other systemic effects.”

May combine two claims.

Increased activity of interneurons enhances synchronous inhibitory neurotransmission and thus occludes plasticity events to a higher extent.

“In particular, the increased activity of interneurons enhances synchronous inhibitory neurotransmission and thus occludes plasticity events to a higher extent.”

May combine two claims.

Extending findings to humans, the difference in basal nAChR expression between adolescents and adults might play a role in initiation of smoking among adolescents, while short-term increased nAChR expression following repeated nicotine may contribute to changing local neuronal network plasticity rules, leading to maintenance of smoking behavior and decreasing likelihood of smoking cessation.

“Extending our findings to humans, the difference in basal nAChR expression between adolescents and adults might play a role in the initiation of smoking among adolescents, whereas the short-term increased expression of nAChRs following repeated nicotine may contribute to changing local neuronal network plasticity rules, thus leading to maintenance of smoking behavior and decreasing the likelihood”

• AssumptionRests on an assumption: The neurobiological findings in adolescent rats can be extrapolated to human adolescent smoking behavior.

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

Repeated or prolonged nicotine exposure increases the number of high-affinity (mainly α4β2*) nicotine-binding sites in heterologous systems, nicotine-treated animals, and post mortem brains of smokers.

“Repeated or prolonged nicotine exposure increases the number of high-affinity (mainly α4β2*) nicotine-binding sites, in heterologous systems (41, 42), nicotine-treated animals (11, 12), and in post mortem brains of smokers (ref. 10; for review, see ref. 43).”

• cites [41] sourceNot checked — no full text of the source
• cites [42] sourceNot checked — no full text of the source
• cites [11] sourceNot checked — no full text of the source
• cites [12] sourceNot checked — no full text of the source
• cites [10] sourceNot checked — no full text of the source

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

Nicotinic receptors, to which acetylcholine and nicotine bind, are important for cognitive functioning.

“Nicotinic receptors, to which both the endogenous ligand acetylcholine and nicotine bind, are important for cognitive functioning (47).”

• cites [47] sourceNot checked — no full text of the source

May combine two claims.

The developmental decline in nAChR expression correlates with functional differences, as nicotine-stimulated 86Rb+ efflux in frontal cortex peaks on P35 and decreases at least until P63.

“This developmental decline in expression correlates with functional differences, as it has been shown that nicotine-stimulated 86Rb+ efflux in frontal cortex peaks on P35, and then decreases at least until P63 (38).”

• cites [38] sourceNot checked — no full text of the source

May combine two claims.

The age effect on 3H-Epi binding cannot be caused by higher plasma nicotine in adolescent rats, because the paradigm caused slightly higher plasma nicotine levels in adults, which did not lead to increased mPFC binding.

“This age effect cannot be caused by higher plasma nicotine in adolescent rats, as our paradigm even caused slightly higher plasma nicotine levels in adults, whereas this did not lead to increased mPFC binding.”

May combine two claims.

Layer II/III nAChRs modulate GABAergic inputs onto pyramidal cells in PFC and are up-regulated by adolescent nicotine exposure.

“Thus, layer II/III nAChRs modulate GABAergic inputs onto pyramidal cells in PFC and are up-regulated by adolescent nicotine exposure.”