Myslivecek J, Trojan S
Institute of Physiology, 1st Faculty of Medicine, Charles University, Albertov 5, 128 00 Prague, Czech Republic.
Sb Lek. 2001;102(3):361-7.
Muscarinic receptors are coupled to G proteins and to date, five subtypes have been characterized. These subtypes differ in their effects on second messenger production. Odd-numbered subtypes activate phospholipase C beta, and then they increase the production of inositoltrisphosphate and diacylglycerol. Even-numbered subtypes inhibit adenylylcyclase. The expression of individual subtypes is quite tissue specific. The heart tissue is realized as M2 predominant organ (in mammals; the muscarinic population in birds consist of M2 and M4 receptors). This article focuses on the possibility of existence of further muscarinic receptor subtypes in avian and mammalian heart in consequences with activation of phosphoinositid metabolism in the heart.
毒蕈碱受体与G蛋白偶联，迄今为止，已鉴定出五种亚型。这些亚型对第二信使产生的影响有所不同。奇数亚型激活磷脂酶Cβ，进而增加肌醇三磷酸和二酰基甘油的产生。偶数亚型抑制腺苷酸环化酶。各个亚型的表达具有很强的组织特异性。心脏组织被认为是以M2为主的器官（在哺乳动物中；鸟类的毒蕈碱受体群体由M2和M4受体组成）。本文重点探讨禽类和哺乳动物心脏中是否存在其他毒蕈碱受体亚型，以及其与心脏中磷酸肌醇代谢激活的关系。
