Vasorelaxant effect of PACAP-27 on canine cerebral arteries and rat intracerebral arterioles.
The vasorelaxant effects of pituitary adenylate cyclase activating polypeptide (PACAP)-27 were examined and compared with those of PACAP-38 and vasoactive intestinal polypeptide (VIP) on isolated canine cerebral arteries and rat intracerebral arterioles in vitro. The addition of PACAP-27, PACAP-38 or VIP resulted in similar concentration-dependent relaxations in both canine basilar arteries and rat intracerebral arterioles. There were regional differences in the PACAP-27-induced relaxations measured in canine cerebral arteries. The maximum relaxation induced by PACAP-27 was significantly lower in the basilar arteries (23.0 +/- 5.6%) than in the rostrally located arteries (proximal middle cerebral arteries: 45.4 +/- 5.7%, anterior cerebral arteries: 55.2 +/- 5.8%). The maximum relaxation induced by PACAP-27 in the basilar arteries was significantly enhanced by mechanical removal of the endothelium (16.4 +/- 4.5% vs. 32.7 +/- 5.8%) as well as by pretreatment with indomethacin or aspirin (12.9 +/- 4.1% vs. 48.7 +/- 6.1% and 46.5 +/- 9.2%, respectively). Incubation of canine cerebral arteries with PACAP-27 in vitro resulted in an increased release of prostaglandin F2 alpha in the buffer from 14.5 +/- 2.1 pg/min/1 mg vessel to 31.1 +/- 4.2 pg/min/1 mg vessel, while other cyclooxygenase cascade metabolites such as prostaglandin E2, thromboxane B2 and 6-keto prostaglandin F1 alpha did not change. These data suggest that the PACAP-27-induced relaxation of canine basilar arteries may be associated with prostaglandin F2 alpha or its precursor, prostaglandin H2.
Anzai
M
M
Department of Neurosurgery, Nagoya University School of Medicine, Japan.
Suzuki
Y
Y
Takayasu
M
M
Kajita
Y
Y
Mori
Y
Y
Seki
Y
Y
Saito
K
K
Shibuya
M
M
D000818:Animals; D001160:Arterioles / Q000187:drug effects; D001488:Basilar Artery / Q000187:drug effects / Q000378:metabolism; D002536:Cerebral Arteries / Q000187:drug effects / Q000378:metabolism; D004285:Dogs; D016232:Endothelins / Q000494:pharmacology; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism; D009479:Neuropeptides / Q000494:pharmacology*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D011448:Prostaglandin Antagonists / Q000494:pharmacology; D011453:Prostaglandins / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology*
C495401:ADCYAP1 protein, human; C495403:Adcyap1 protein, rat; D016232:Endothelins; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D011448:Prostaglandin Antagonists; D011453:Prostaglandins; D014665:Vasodilator Agents; D014660:Vasoactive Intestinal Peptide