Cited by 958Advanced Drug Delivery SystemsBarrier Structure and Function StudiesRNA Interference and Gene Delivery

Delivery of insulin-like growth factor-I to the rat brain and spinal cord along olfactory and trigeminal pathways following intranasal administration

Thorne, R.G., Pronk, G.J., Padmanabhan, V., Frey, W.H.·2004·Neuroscience

Abstract

We investigated the CNS delivery of insulin-like growth factor-I (IGF-I), a 7.65 kDa protein neurotrophic factor, following intranasal administration and the possible pathways and mechanisms underlying transport from the nasal passages to the CNS. Anesthetized adult male Sprague-Dawley rats were given [125I]-IGF-I intranasally or intravenously and then killed by perfusion-fixation within 30 min. Other animals were killed following cisternal puncture and withdrawal of cerebrospinal fluid (CSF) or intranasal administration of unlabeled IGF-I or vehicle. Both gamma counting of microdissected tissue and high resolution phosphor imaging of tissue sections showed that the tissue concentrations and distribution following intranasal administration were consistent with two routes of rapid entry into the CNS: one associated with the peripheral olfactory system connecting the nasal passages with the olfactory bulbs and rostral brain regions (e.g. anterior olfactory nucleus and frontal cortex) and the other associated with the peripheral trigeminal system connecting the nasal passages with brainstem and spinal cord regions. Intranasal administration of [125I]-IGF-I also targeted the deep cervical lymph nodes, consistent with their possible role in lymphatic drainage of both the nasal passages and the CNS. Cisternal CSF did not contain [125I]-IGF-I following intranasal administration. Intravenous [125I]-IGF-I resulted in blood and peripheral tissue exposure similar to that seen following intranasal administration but CNS concentrations were significantly lower. Finally, delivery of IGF-I into the CNS activated IGF-I signaling pathways, confirming some portion of the IGF-I that reached CNS target sites was functionally intact. The results suggest intranasally delivered IGF-I can bypass the blood-brain barrier via olfactory- and trigeminal-associated extracellular pathways to rapidly elicit biological effects at multiple sites within the brain and spinal cord.

Integrity signals

Registry

Crossref · 10.1016/j.neuroscience.2004.05.029

Cites

106 of 106 references verified0 citation errors · 0 not checkable

Statistics

Recomputing p-values needs the paper’s full text.

Claims the paper makes

This paper’s full text isn’t openly available, so its claims and self-check weren’t run. The registry and citation checks still apply.

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Frey II et al. confirmed that IGF1 reached central nervous system target sites in rats after administration of [125I]-labeled IGF1.

    “Frey II et al. investigated the delivery of IGF1 to CNS, confirming they reached CNS target sites of rats by administering a mixture of [125I]-labeled IGF1.179”
  • Through the nasal route, a drug can access the brain directly along the trigeminal and olfactory nerves located in the upper part of the nasal cavity.

    “Through the nasal route, the drug can access the brain directly along the trigeminal and olfactory nerves, which are located in the upper part of the nasal cavity.”

    From Nanoemulsions for “Nose-to-Brain” Drug Delivery (2019) · cites this paper as [8]

  • Olfactory and trigeminal pathways are the only routes by which the brain is connected to the outside environment.

    “Olfactory and trigeminal pathways are the only routes by which the brain is connected to the outside environment [8,9].”

    From Nanoemulsions for “Nose-to-Brain” Drug Delivery (2019) · cites this paper as [8]

  • In Sprague-Dawley rats, intranasally administered insulin-like growth factor-1 rapidly acts on multiple sites within the brain and spinal cord.

    “Experiments in Sprague-Dawley rats relying on gamma counting and high-resolution phosphor imaging of tissue sections show that IN administered insulin-like growth factor-1 rapidly acts on multiple sites within the brain and spinal cord.”

    From Intranasal insulin (2021) · cites this paper as [31]

Cites

Flagged first, then by citations

Cited by

Sorted by citations

Authors
Thorne, R. G., Pronk, G. J., Padmanabhan, V., & Frey, W. H.
Affiliations
Regions Hospital (US)
Corresponding author
Frey, W.H.
Venue
Neuroscience
Publisher
Elsevier BV
Published
2004-01
Volume
127
Issue
2
Pages
481-496
ISSN
0306-4522 (ISSN-L)
OpenAlex
W2077756131
Cited by
958
References
106
Citations by year
2026: 33 · 2025: 47 · 2024: 55 · 2023: 52 · 2022: 50 · 2021: 64 · 2020: 54 · 2019: 46 · 2018: 47 · 2017: 58 · 2016: 44 · 2015: 40 · 2014: 51 · 2013: 46 · 2012: 52
FWCI
14.62
Type
journal article
Language
en
Open access
closed
Locations
  • Neuroscience (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Life Sciences › Pharmacology, Toxicology and Pharmaceutics › Pharmaceutical Science › Advanced Drug Delivery Systems
  • Life Sciences › Neuroscience › Neurology › Barrier Structure and Function Studies
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › RNA Interference and Gene Delivery
Keywords
insulin-like growth factor I, intranasal drug delivery, olfactory pathway, trigeminal pathway, blood-brain barrier bypass, spinal cord, olfactory bulb, anterior olfactory nucleus, deep cervical lymph nodes, cerebrospinal fluid, IGF-1 signaling, neurotrophic factor delivery
MeSH terms
Administration, Intranasal, Animals, Blood-Brain Barrier, Brain, Cerebrospinal Fluid, Dose-Response Relationship, Drug, Insulin-Like Growth Factor I, Iodine Radioisotopes, Lymph Nodes, Male, Olfactory Nerve, Olfactory Pathways, Reaction Time, Spinal Cord, Trigeminal Nerve, Signal Transduction, Rats, Sprague-Dawley, Rats

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review