Pre- and Postsynaptic Effects of Angiotensins in the Femoral Artery of Spontaneously Hypertensive and Wistar-Kyoto Rats
作者:
Masanobu Urabe,
Che Su,
Tony J.-F. Lee,
期刊:
Journal of Vascular Research
(Karger Available online 1987)
卷期:
Volume 24,
issue 1-2
页码: 1-10
ISSN:1018-1172
年代: 1987
DOI:10.1159/000158666
出版商: S. Karger AG
关键词: Angiotensin I;Angiotensin II;Femoral artery;Spontaneously hypertensive rat;Wistar-Kyoto rat;Endothelium;Captopril
数据来源: Karger
摘要:
The effects of angiotensin I (AI) and angiotensin II (AII) on ring segments of femoral arteries from spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) were studied. AI and AII elicited significantly greater direct contractile response in arteries from SHR than those from WKY. These peptides also potentiated the contractile response to transmural adrenergic nerve stimulation (TNS) in both preparations, but to a greater extent in those of WKY than SHR, without potentiating the contractile response to exogenous norepinephrine (NE). The potentiation of the TNS response and direct contraction caused by AI were markedly attenuated by captopril, an AI-converting enzyme inhibitor. Destruction of endothelium failed to alter the contractile response to AI in both WKY and SHR but augmented that to AII in WKY. Isoproterenol and salbutamol produced significant potentiation of TNS response only in arteries of SHR. Yohimbine and prostaglandin F2α potentiated TNS response to a similar extent in arteries of WKY and SHR. These results suggest that AII locally generated from AI can act postsynaptically to cause contraction and presynaptically to promote adrenergic neurotransmission in the isolated rat femoral artery. The AI to AII conversion appears to take place mainly at sites other than endothelial cells. The postsynaptic effect of AII is greater in SHR than WKY, but its presynaptic effect is diminished in SHR unlike some other agents which facilitate adrenergic neurotransmission, and unlike that in mesenteric arteries of SHR
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