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On the Blood‐Brain Barrier to Peptides: [ 3 H]βCasomorphin‐5 Uptake by Eighteen Brain Regions In Vivo
Author(s) -
Ermisch A.,
Ruhle H.J.,
Neubert K.,
Hartrodt B.,
Landgraf R.
Publication year - 1983
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1983.tb00816.x
Subject(s) - blood–brain barrier , endocrinology , medicine , in vivo , chemistry , biology , central nervous system , microbiology and biotechnology
After intracarotid injection of [ 3 H]β‐casomorphin‐5 (βCM5) in rats, the accumulation of radioactivity was determined in 18 brain regions and the anterior pituitary. The relative accumulation in all regions significantly exceeded that of [ 3 H]inulin by a factor of 2.5, indicating a low but measurable brain uptake of the peptide. In blood‐brain barrier‐free areas, the accumulation of radioactivity was 15‐fold higher than in blood‐brain barrierprotected areas. The relative accumulation was not dependent on the total βCM5 concentration in the range of 0.3–1.1μ M , and was not depressed by 400μ M L‐tyrosine. We conclude that βCM5, like other peptides, is accumulated in the blood‐brain barrier‐free areas to a relatively high but differing degree, whereas in the areas with a tight endothelium the accumulation is relatively low and nearly uniform. A binding to endothelial cells may contribute to the low accumulation of βCM5, especially in blood‐brain barrier‐protected areas.