大鼠处理普奈洛尔后改变α_1受体亚型介导的心功能(英文)  

Altered α_1-adrenoceptor subtypes mediated cardiac function after treatment of propranolol to rats

作　　者：李婉[1] 张缨[1] 王晓良[1] 

机构地区：[1]中国医学科学院中国协和医科大学药物研究所

出　　处：《中国药理学报》1997年第3期237-240,共4页Acta Pharmacologica Sinica

基　　金：Project supported by National Science Foundation of China for Outstanding Young Scientists, № 39425014

摘　　要：目的:研究普奈洛尔(Pro)作用后,大鼠心肌α_(1A)和α_(1B)受体亚型介导正性肌力和正性频率变化.方法:测定Pro大鼠和正常鼠左心室乳头状肌和右心房收缩力和心率.结果:给予Pro后,苯肾上腺素(Phe)使乳头状肌收缩力由53±17 mg增加到90±18 mg(P<0.05).Pro和对照组收缩力分别增加20±12和5±5 mg(P<0.05).氯乙基可乐定使两组收缩力变化无区别.5-甲基乌拉地尔存在时Phe使Pro组收缩力增加13±5mg,对照组无变化.正常和心率抑制时,Phe使两组动物α_(1B)介导心率增加无差别.结论:β受体阻断,α_1介导正性肌力增加主要由α_(1B)作用增强引起.AIM: To study inotropic and chronotropic effects mediated by α1A- and α1B-adrenoceptors after 5-d propranolol (Pro) treatment. METHODS: The positive inotropic and chronotropic effects mediated byα1A and α1B subtypes were determined on isolated left ventricular papillary muscles and right atrium in Pro- and NaCl-treated rats. RESULTS: The basic contractility of papillary muscles induced by phenylephrine (Phe) was 90 ±18 mg in Pro-treated rats and 53 ± 17 mg in control group (P<0.05). The increment on force of contraction was 20 ±12 mg in Pro-pretreated rats and 5 ± 5 mg in NaCl-treated rats ( P < 0.05 ). After preincubated with chloroethylclonidine, the increment on force of contraction was reduced in Pro-treated rats, but was not much changed in control group. Phe in presence of 5-methylurapidil induced positive inotropic effect with 13± 5 mg in Pro-treated group, but not in NaCl-treated rats. Under the normal and the inhibited cardiac state, the maximal increment in beat rate mediated by α1B showed no difference between the Pro-treated and NaCl-treated rats. CONCLUSION: After chronic treatment of Pro, α1-adrenoceptor-mediated positive inotropic effect in rat heart was improved, which was mainly induced by stimulation of α1B when β-adrenoceptors were blocked.

关 键 词：心肌收缩 心率 普奈洛尔 

分 类 号：R972[医药卫生—药品]