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早在1948年,Ahlquist就把肾上腺素受体分成α—和β—两个亚型。1967年Lands等根据几种β—受体激动剂对受体激动的强度,把β—肾上腺素受体进一步分成β_1-和β_2-受体两个亚型。一般认为,β_1-受体主要分布在心脏,兴奋时产生正性变力和变时效应;而β_2-受体则主要分布在支气管、血管、子宫及胃肠道平滑肌等组织中,兴奋时或使支气管、血管扩张,或使胃肠道平滑肌松驰。但近有实验证明,这种分类已难以解释β_2-受体激动剂的某些心血管作用。实验表明,β_2
As early as 1948, Ahlquist divided adrenergic receptors into alpha- and beta-two subtypes. In 1967, Lands et al divided the β-adrenoceptors into two subtypes, β_1- and β_2-receptors, according to the receptor agonist intensity of several β-agonists. It is generally believed that the β 1 -receptors are mainly distributed in the heart and produce positive and time-varying effects in excitement. The β 2 -receptors are mainly distributed in the bronchial, vascular, uterine and gastrointestinal smooth muscle tissues, Bronchial, vascular dilatation, or gastrointestinal smooth muscle relaxation. However, recent experiments have shown that this classification has been difficult to explain some of the cardiovascular effects of β 2 -receptor agonists. Experiments show that, β_2