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Cited by 114Barrier Structure and Function StudiesNeuropeptides and Animal PhysiologyAmino Acid Enzymes and Metabolism

Blood-brain barrier permeability to leucine-enkephalin,d-Alanine2-d-leucine5-enkephalin and their N-terminal amino acid (tyrosine)

Zlokovic, Berislav V., Begley, David J., Chain-Eliash, Daniel G.·1985·Brain Research
DOI 10.1016/0006-8993(85)90423-8
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Abstract

The permeability of the blood-brain barrier to [tyrosyl-3,5-3H]enkephalin-(5-L-leucine) (abbreviated to Leu-Enk) and of its synthetic analogue D-alanine2-[tyrosyl-3,5-3H]enkephalin-(5-D-leucine) (abbreviated to D-Ala2-D-Leu5-Enk) was studied, in the adult rat, by means of Oldendorf's27 intracarotid injection technique. The brain uptake index (BUI) corrected for residual vascular radioactivity was about the same for both peptides, indicating a low extraction from the blood during a 5- or 15-s period of exposure to the peptides. Transport of Leu-Enk was not saturated by unlabelled Enk at a concentration as high as 5 mM but was completely abolished by 5mM tyrosine and by the inhibitor of aminopeptidase activity, bacitracin (2 mM). Also the typical L-transport system substrate, 2-aminobicyclo(2,2,1)heptane-2 carboxylic acid (BCH)9 at 10 mM concentration markedly reduced (by 80%) Leu-Enk uptake by the brain. In contrast, brain uptake of D-Ala2-D-Leu5-Enk was reduced only to about one-half of its control value by bacitracin or by 25% by BCH. Brain uptake for L-tyrosine was typically large and markedly inhibited by BCH but not inhibited by 5 mM unlabelled Leu-Enk. These results show that the measurable but low first-pass extractions for enkephalins are not representative of the uptake of these peptides into the brain, but rather reflect their extreme sensitivity to enzymatic degradation with a release of the N-terminal tyrosine residue. The results also suggest that small amounts of…

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  • In general, the transport rate of circulating peptides is slower than nutrient transport across the blood-brain barrier.

    “In general, the transport rate of circulating peptides is slower than nutrient transport across the BBB (695).”

    From Blood-Brain Barrier: From Physiology to Disease and Back (2019) · cites this paper as [695]

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Authors
Zlokovic, B. V., Begley, D. J., & Chain-Eliash, D. G.
Affiliations
King's College London (GB)
Corresponding author
Begley, David J.
Venue
Brain Research
Publisher
Elsevier BV
Published
1985-06
Volume
336
Issue
1
Pages
125-132
ISSN
0006-8993 (ISSN-L)
DOI
10.1016/0006-8993(85)90423-8
OpenAlex
W2068144717
Cited by
114
References
1
Citations by year
2025: 1 · 2024: 3 · 2023: 1 · 2022: 3 · 2020: 1 · 2019: 3 · 2018: 3 · 2017: 3 · 2016: 5 · 2015: 15 · 2014: 4 · 2013: 2 · 2012: 6
FWCI
5.60
Type
journal article
Language
en
Open access
closed
Licence
www.elsevier.com/tdm/userlicense/1.0/ (tdm)
Locations
  • Brain Research (publishedVersion)
  • PubMed (publishedVersion)
Funders
Wellcome Trust
Topics
  • Life Sciences › Neuroscience › Neurology › Barrier Structure and Function Studies
  • Life Sciences › Neuroscience › Cellular and Molecular Neuroscience › Neuropeptides and Animal Physiology
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Biochemistry › Amino Acid Enzymes and Metabolism
Keywords
blood-brain barrier permeability, leu-enkephalin, DADLE, brain uptake index, aminopeptidase inhibition, bacitracin, BCH, peptide transport, enzymatic degradation, first-pass extraction, intracarotid injection, rat brain
MeSH terms
Animals, Blood-Brain Barrier, Enkephalin, Leucine, Female, Male, Rats, Inbred Strains, Tyrosine, Enkephalin, Leucine-2-Alanine, Rats

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