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药理学 Labetalol是一种水杨酰胺衍化物,是一种对α-和β-肾上腺素能受体均有作用的特异性竞争拮抗剂,其结构如下: α-和β-受体的阻滞:在体外、离体动物组织和整体动物,Labetalol是α-受体的竞争性拮抗剂,也是β-受体的非选择性拮抗剂。它对β-受体无内源性激动(拟交感)活性。Labetalol在大于阻滞肾上腺素能受体所需的剂量,对心肌具有某些直接抑制作用,但在治疗高血压所用的剂量,这种作用似无临床意义。因此在β-受体,Labetalol的作用类似心得安,但比心得安小。在猫脾脏,Labetalol是一突触后α-受体拮抗剂,因而其对α-受体的作用可能与哌唑嗪类似。离体组织研究表明,Labetalol对β-受体的作
Pharmacology Labetalol is a salicylamide derivative that is a specific competitive antagonist of both α- and β-adrenergic receptors and has the following structure: Blocking of α- and β-receptors : Labetalol is a competitive antagonist of alpha-receptors in vitro, ex vivo animal tissues and whole animals and is also a nonselective antagonist of beta-receptors. It has no intrinsic agonistic (sympathomimetic) activity on the beta-receptor. Labetalol has some direct inhibition of cardiac muscle at doses greater than those required to block adrenergic receptors, but this effect seems clinically significant at the dose used to treat hypertension. Therefore, in the β-receptor, Labetalol similar effect of propranolol, but less than the peace of mind. In the spleen of cats, Labetalol is a post-synaptic alpha-receptor antagonist and therefore its effect on alpha-receptors may be similar to that of prazosin. In vitro studies have shown that Labetalol does beta-receptor