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Angiotensin II receptor binding sites in brain microvessels

Journal Article · · Proc. Natl. Acad. Sci. U.S.A.; (United States)
The authors assessed the specific binding of /sup 125/I-labeled angiotensin II (/sup 125/I-Ang II) to particulate fractions of the cerebral cortex and cerebellum and to microvessels obtained by bulk isolation from these two brain regions in the dog. /sup 125/I-Ang II binds to cerebral and cerebellar microvessels in a specific, saturable, and reversible manner and with high affinity (dissociation constant about 1 nM). Maximal binding of /sup 125/I-Ang II to brain microvessels was about 2-fold higher than the maximal binding to particulate fractions of the cerebellum and more than 15-fold higher than that of the cerebral cortex. Furthermore, finding that analogues of Ang II displace specific /sup 125/I-Ang II binding to brain microvessels in a rank order that correlates with their pharmacological activities confers biological relevance on the ligand-binding studies. These results strongly suggest that specific Ang II receptor binding sites are present in brain microvessels. Such Ang II receptors may have an important role in regulating the microcirculation of the brain.
Research Organization:
Case Western Reserve Univ. School of Medicine, Cleveland, OH
OSTI ID:
6300421
Journal Information:
Proc. Natl. Acad. Sci. U.S.A.; (United States), Journal Name: Proc. Natl. Acad. Sci. U.S.A.; (United States) Vol. 82:18; ISSN PNASA
Country of Publication:
United States
Language:
English