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Cerebral Vascular Adenylate Cyclase: Evidence for Coupling to Receptors for Vasoactive Intestinal Peptide and Parathyroid Hormone
Author(s) -
Huang Minta,
Rorstad O. P.
Publication year - 1984
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.1471-4159.1984.tb12808.x
Subject(s) - vasoactive intestinal peptide , secretin , endocrinology , medicine , cyclase , adenylate kinase , parathyroid hormone , receptor , parathyroid hormone receptor , pituitary adenylate cyclase activating peptide , chemistry , biology , neuropeptide , hormone receptor , calcium , secretion , cancer , breast cancer
We have studied the responsiveness of vascular adenylate cyclase to vasoactive intestinal peptide (VIP) and parathyroid hormone (PTH) using preparations of cerebral microvessels and arteries. Cerebral microvessels obtained from rats, guinea‐pigs, cattle, and pigs all responded potently to bovine (b) PTH‐(1‐34), whereas considerable between‐species variability was observed in the responsiveness to VIP. The homologous peptide to VIP, PHI (porcine heptacosapeptide), stimulated adenylate cyclase in both rat microvessels and a broken‐cell preparation of bovine arteries. The ED 50 values for activation of bovine arterial adenylate cyclase by VIP, PHI, and bPTH‐(1‐34) were 6.9 n M , 10 n M , and 100 n M , respectively, with the following order of efficacy: VIP = PHI > bPTH‐(1‐34). The other related peptides, hpGRF (human pancreatic growth hormone releasing factor), secretin, and glucagon, and the fragment VIP‐(10‐28) were inactive. The PTH antagonist, [Nle 8 , Nle 18 , Tyr 34 ]bPTH‐(3‐34) amide, inhibited bPTH‐(1‐34) activation of vascular adenylate cyclase but did not affect activation by VIP using either microvessels or arteries. VIP or PHI demonstrated an additive effect with bPTH‐(1‐34) on vascular adenylate cyclase activity. However, the effects of VIP and PHI were nonadditive with each other. These data suggest that VIP and bPTH‐(1‐34) activate cerebral vascular adenylate cyclase by interacting with pharmacologically distinct receptors, whereas PHI and VIP likely interact with a common receptor.