Vascular responsiveness to periarterial electrical nerve stimulation on canine ophthalmic arteries
作者:
OhkuboHirofumi,
ChibaShigetoshi,
期刊:
Current Eye Research
(Taylor Available online 1988)
卷期:
Volume 7,
issue 6
页码: 607-613
ISSN:0271-3683
年代: 1988
DOI:10.3109/02713688809031817
出版商: Taylor&Francis
数据来源: Taylor
摘要:
Both periarterial electrical stimulation (ES) and intraluminal application of noreplnephrine (NE) produced a vasoconstriction in the isolated canine ophthalmic artery (OA). The ES-induced vasoconstrictor response was markedly inhibited by treatment with tetrodotoxin and slightly but significantly depressed by xylazine, a selective alpha-2 adrenoceptor agonist. Moreover, the ES-induced response was enhanced by either DG-5128, a selective alpha-2 adrenoceptor antagonist, or angiotensin II. The inhibitory effect of bunazosin on the ES-induced response was significant, but it was rather small compared with that on the NE-induced response. The NE-induced constriction was not affected by xylazine and DG-5128, but significantly enhanced by angiotensin II. These results indicate that (1) the ES-induced response is mediatedviasympathetic nerve activation, (2) there are inhibitory prejunctional alpha-2 adrenoceptors, (3) there are more postjunctional alpha-1 than postjunctional alpha-2 adrenoceptors in canine OAs, and (4) prejunctional angiotensin II receptors may exist in isolated OA preparations.
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