Acetylcholine receptors from electroplax membranes: in vitro and in situ properties.
Acetylcholine receptors from electroplax membranes: in vitro and in situ properties.
复制标题
Electroplax 膜的乙酰胆碱受体：体外和原位特性。
DOI：
10.1007/978-1-4615-9281-5_17
复制
发表时间：
1982
影响因子：
--
通讯作者：
Paraschos,A
中科院分区：
文献类型：
--
作者：
Martinez-Carrion,M;Gonzalez-Ros,JM;Llanillo,M;Paraschos,A
细胞表面受体能够识别细胞通讯的化学介质，并为生物反应产生特定的信号。在某些神经元突触、脊椎动物神经肌肉终板和某些弹性支的电组织中，化学介质是乙酰胆碱，受体是突触后跨膜蛋白。1 .乙酰胆碱结合诱导了短寿命（约3 ms）膜通道的打开，这些通道可渗透到直径小于8 Å的单价或二价阳离子。这一事件导致电导增加和膜的去极化。虽然人们一致认为乙酰胆碱受体(AcChR)*与离子通道在膜内偶联，但受体结合位点与离子通道位点的关系尚不清楚。当神经递质或引起类似反应的各种化合物（激动剂）的浓度保持不变时，活性受体通道的数量缓慢下降，这种现象被称为脱敏。一般来说，受体的激活是由于对AcChR静息状态亲和力较低的激动剂的识别。随着结合的缓慢发展，脱敏随之发生，这与那些激动剂的高AcChR亲和力状态的出现相似。1,2
Cell surface receptors are capable of recognizing chemical mediators of cellular communication and generate a specific signal for a biological response. At certain neuronal synapses, the vertebrate neuromuscular end plate and the electric tissue of certain elasmobranch, the chemical mediator is acetylcholine and the receptor is a postsynaptic transmembrane protein.1Acetylcholine binding induces opening of short lived (∿ 3 ms) membrane channels permeable to monovalent or divalent cations of less than 8 Å in diameter.1This event leads to a conductance increase and a depolarization of the membrane. While it is agreed that the acetylcholine receptor (AcChR)* and the ionic channel are coupled in the membrane, the relationship of the receptor binding sites and the ionic channel sites is still unclear. When the neurotransmitter concentration or that of a variety of compounds eliciting similar responses (agonists) is maintained, the number of active receptor channels slowly declines and the phenomenon is known as desensitization. In general, activation of the receptors results from recognition of agonists with low affinity for the resting state of the AcChR. As binding slowly develops desensitization ensues which parallels the appearance of a state of high AcChR affinity for those agonists.1,2