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肾上腺素能受体(以下简称受体)的亚型β受体的β_1(心脏和脂肪组织)和β_2(平滑肌)两种亚型均可与腺苷环化酶相偶联。前一亚型的拮抗剂为 metoprolol 和心得宁;后一亚型的拮抗剂为 butoxamine。α_1受体即突触后α受体,儿茶酚胺作用时可引起血管及其他平滑肌收缩以及肝脏某些代谢作用;α_2受体存在于突触前及突触后各部位。对突触前α受体的研究,阐明了儿茶酚胺反馈性抑制交感神经末梢释放去甲肾上腺素,由于它对某些激动剂如氯压啶和拮抗剂育亨宾有较大的亲和力,因此它与典型的突触后α受体在药理学上有明显
The beta 1 receptors (cardiac and adipose tissue) and beta 2 (smooth muscle) subtypes of the adrenergic receptor (hereinafter referred to as the receptor) are both conjugated to adenylyl cyclase. The antagonists for the former subtype are metoprolol and norepinephrine; the latter subtype antagonist is butoxamine. α_1 receptor that is post-synaptic α receptor, catecholamine can cause vascular and other smooth muscle contraction and some of the role of the liver metabolism; α_2 receptor exists in the pre-synaptic and post-synaptic parts. Studies of the presynaptic alpha receptors elucidate that catecholamines feedback inhibit sympathetic nerve endings to release norepinephrine because of its greater affinity for certain agonists such as clonidine and the antagonist yohimbine, Pharmacologically distinct from the typical postsynaptic alpha receptors