文档介绍：Chapter 10 Adrenoceptor Agonists
Pharmacology
Instructor : Lei Linsheng 雷林生
Drugs that mimic the actions of epinephrine or norepinephrine would be expected to have a wide range of effects.
An understanding of the pharmacology of these agents is thus a logical extension of what we know about the physiologic role of the catecholamines.
基本结构为β-苯乙胺(Phenylethylamine),苯环3、4位碳上都有羟基形成儿茶酚,称儿茶酚胺类(catecholamines)。T灭活,作用时间短;对中枢作用弱。去掉一个羟基,外周作用减弱,作用时间延长。两个羟基都去掉,外周作用减弱,中枢作用加强。
烷胺侧链α碳原子上氢被甲基取代,可阻碍MAO的氧化,作用时间延长;易被摄取-1所摄入,在神经元内存在时间长,促进递质释放。
氨基末端的取代基团从氢、甲基到叔丁基,对α受体的作用逐渐减弱,对β受体的作用却逐渐加强。
Classification
alpha agonists:
α1 , α2 , α1 and α2
mixed αand βagonists
beta agonists: β1, β2
dopamine agonists: D1, D2
Ⅰ. α agonists
Noradrenaline 去甲肾上腺素
( NA, Norepinephrine)
acts mainly on α receptors ,
a little bit effect onβ1
ineffective given orally
subcutaneous injection -absorbed poorly, induces tissue necrosis
should be given by
Pharmacological effects
Blood vessels
very strong constriction effect on blood vessels
dilation of coronary blood vessels
Heart
some effect as Adr.-- weak -- less likely to cause arrhythmia
Blood pressure
increases systolic and diastolic
pressure -- increases BP
Clinical Uses
1. Hypotension
–induced by drug intoxication
CNS inhibitors , general
anesthetics ,etc
Chlorpromazine 氯丙嗪 intoxication