权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Reguratory mechanism of hypotensive responses to muscarinic cholinergic stimulation through the adrenergic receptor system.

通过肾上腺素能受体系统对毒蕈碱胆碱能刺激的低血压反应的调节机制。

基本信息

批准号：
05671836
负责人：
ISHII Kunio
金额：
$ 1.34万
依托单位：
University of Shizuoka
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

项目摘要

The following findings were obtained in pentobarbital (30mg/kg, i.v) -anesthetized dogs.1.Phenylephrine (Phe) infusions into the right cephalic vein at a rate between 0.3 and 10mug/kg induced persistent and dose-dependent pressor responses through stimulation of alpha-adrenoceptors on the vascular smooth muscle cells.2.Infusions of Phe at a rate in the above range suppressed ACh-induced hypotension in a manner that is dependent on the dose and the period of time of Phe infusion.After Phe infusion at a rate of 3 mug/kg for 120 min shifted the dose-response curve for the hypotensive responses to ACh to the right by about 80-times.3.Inhibitory effect of Phe infusions on the ACh-induced hypotension was long-lasting.For instance, no recovery in the inhibition was observed for at last 120 min after cessation of a Phe infusion that was carried out at a rate of 3 mug/kg for 120 min.Blood pressure returned to the basal level immediately after stopping the Phe infusions.4.Other alpha-adrenoceptor agonists, methoxamine and norepinephrice, and a non-adrenerigic vasoconstrictor, angiotensin II,also inhibited ACh-induced hypotension in a similar manner as observed with Phe, suggesting importance of elevation of blood pressure in this phenomenon.5.Phe infusions little affected hypotensive responses to histamine, sodium nitroprusside, carbachol and methacholine.6.The inhibitory effect of Phe infusions on ACh-induced hypotension was reversed by treatment of dogs with a cholinesterase inhibitor, neostigmine.In addition, only small inhibition was observed when ACh was administered into the left ventricle, instead of vein, even after Phe infusions at a rate of 3 mug/kg for 120min.These results suggest that acceleration of ACh metabolism in the lung is responsible for Phe-induced inhibition of ACh responses.In other animal species examined so far, including rats, guinea-pigs and rabbits, Phe infusions failed to affect hypotensive responses to ACh.

在戊巴比妥中获得了以下结果（30mg/kg，在麻醉狗的右侧头静脉内注入苯丙氨酸（Phe）0.3 ~ 10 μ g/kg，通过刺激血管平滑肌细胞上的α-肾上腺素能受体，引起持续的、剂量依赖性的升压反应。以3 μ g/kg的速率输注Phe 120分钟后，ACh引起的降压反应的量效曲线右移约80倍。例如，停止以3 μ g/kg的速率进行120分钟的Phe输注后，在最后120分钟内没有观察到抑制的恢复。停止Phe输注后，血压立即恢复到基础水平。4.其它α-肾上腺素受体激动剂，甲氧胺和去甲肾上腺素，以及非肾上腺素血管收缩剂，血管紧张素II，也以与Phe相似的方式抑制ACh诱导的低血压，提示在这种现象中血压升高的重要性。5. Phe输注几乎不影响对组胺，硝普钠，6.用胆碱酯酶抑制剂新斯的明治疗狗，可以逆转苯丙氨酸输注对乙酰胆碱诱导的低血压的抑制作用。此外，当乙酰胆碱被注入左心室而不是静脉时，即使在以3 μ g/kg的速率输注苯丙氨酸120分钟后，也只观察到很小的抑制作用。这些结果表明，肺中乙酰胆碱代谢的加速是苯丙氨酸诱导的乙酰胆碱反应抑制的原因。在迄今为止研究的其他动物物种中，包括大鼠、豚鼠和兔，Phe输注未能影响ACh的兴奋反应。