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.

以下发现是在五核（30mg/kg，i.v）的止血狗中获得的。1。苯肾上腺素（PHE）在右头静脉中输注以0.3至10mug/kg的速率在0.3至10毫克/kg的速率中，可诱导的持久和剂量依赖的压力通过刺激的抗抑制作用，以平稳的速度抚摸。上述范围内的速率以一种取决于剂量和pHE输注的时间的方式抑制了ACH诱导的低血压。在以3杯/千克的速度输注120分钟后，PHE输注速率将剂量 - 反应曲线转移到右上的剂量响应，以使ACH的hypimentions the Inflistions inthimentive of ACH的实现效果。停止以3杯/kg的速度进行PHE输液后，在最后120分钟观察到抑制作用，持续了120分钟。在停止PHE输液后立即恢复至基础水平。 ACH诱导的低血压的低血压与PHE观察到的相似的方式表明，在这种现象中，血压升高的重要性很少。5。Phe输注几乎没有影响对组胺，硝化钠，卡巴乔尔钠，卡巴乔尔和甲基酚的降压反应。6。6。对狗的抑制作用对狗的抑制作用的抑制作用，对狗的抑制作用对雷神的抑制作用，而对雷神的抑制作用是雷神的抑制作用。 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输注未能影响对ACH的降压反应。