可乐宁(clonidine)是一种人工合成的α_2受体激动剂,它可抑制中枢交感神经的传出冲动,产生强大的降压效应,被广泛用于各型高血压的治疗。去甲肾上腺素和α-甲基多巴是体内α_2受体特异性配基,但其作用与可乐宁不同。在网状外侧核内注射微量的可乐宁,可引起明显的降压作用,但注射去甲肾上腺素或α-甲基多巴则不能;去甲肾上腺素可激活人血小板腺苷 Clonidine is a kind of synthetic α 2 receptor agonist, which can inhibit the outgoing impulses of the central sympathetic nerve and has a strong antihypertensive effect. It is widely used in the treatment of various types of hypertension. Norepinephrine and alpha-methyl dopa are alpha 2 receptor-specific ligands in the body, but their effects differ from those of clonidine. Injection of trace amounts of clonidine in the reticular nucleus can cause significant antihypertensive effects, but not norepinephrine or alpha-methyl dopa; noradrenaline activates human platelet adenosine