毒蕈碱型乙酰胆碱受器(muscarinic acetylcholine receptors)是一大类固定在细胞膜上的乙酰胆碱受器，其对毒蕈碱比对烟碱（尼古丁）更为敏感。反过来对烟碱比较敏感的则称为烟碱型乙酰胆碱受体。毒蕈碱与烟碱两者皆为生物碱（alkaloid）。许多药品与其他类物质（例如匹鲁卡品与东莨菪碱）常以促进剂或拮抗剂的角色发生作用，并且其作用是仅单一针对毒蕈碱受器或单一针对烟碱受器，使得这样的受器分类显得有用。
背景
生理学
蕈毒碱型受器的型态
受器形式的多样性
M2毒蕈碱受体位于心脏，在心脏中，它们通过减慢去极化速度，使心率降至正常基线窦性心律以下。在休息条件下的人类中，迷走神经活动高于交感神经活动。因此，抑制M2受体（例如，阿托品）会导致心率升高。它们还适度降低了心房肌肉的收缩力，并降低了房室结的传导速度。它也可以稍微降低心室肌肉的收缩力。
通常，M2毒蕈碱受体通过Gi型受体起作用，这会导致细胞内cAMP的降低，电压门控Ca2+通道的抑制和K+外排的增加，通常会导致抑制型效应。
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M4受体在中枢神经系统中被发现。M4受体通过Gi受体起作用，从而降低细胞中的cAMP，因此通常产生抑制作用。如果受到毒蕈碱兴奋剂刺激可能导致支气管痉挛。M4受体也位于外周组织的红系祖细胞中。M4受体调节cAMP通路从而调控红系祖细胞分化。靶向M4受体治疗对红细胞生成素治疗无效的骨髓增生异常综合征和贫血。
M5受体的位置尚不清楚。
参见
文献
- ^ Simon MI, Strathmann M, Gautam N. Diversity of G proteins in signal transduction. Science. 1991, 252 (5007): 802–8. PMID 1902986. Fulltext (PDF, subscription required) （页面存档备份，存于互联网档案馆）
- ^ Mark L Dell'Acqua, Reed C Carrol, Ernest G Peralta. Transfected m2 muscarinic acetylcholine receptors couple to G alpha i2 and G alpha i3 in Chinese hamster ovary cells. Activation and desensitization of the phospholipase C signaling pathway. Journal of Biomedical Chemistry. 1993, 268 (8): 5676–85. PMID 8449930. Free Fulltext (PDF)
- ^ Messer, Jr, William S. Acetylcholine. 20 Jan 2000. University of Toledo. Accessed 11 September 2005.
- ^ Johnson, Gordon E. PDQ Pharmacology. 2nd edition. BC Decker. 2002. ISBN 1550091093
- ^ Richelson, Elliot. Cholinergic Transduction. The Fourth Generation of Progress. The American College of Neuropsychopharmacology. 2000.
- ^ see Johnson, 2002.
- ^ see Richelson, 2000.
- ^ G protein diversity and complexity in G-protein Signaling. RA Fisher. University of Iowa, Lecture Notes, 2004.
- ^ see Richelson, 2000.
- ^ Burford NT, Nahorski SR. Muscarinic m1 receptor-stimulated adenylate cyclase activity in Chinese hamster ovary cells is mediated by Gs alpha and is not a consequence of phosphoinositidase C activation. Biochemistry Journal. 1996, 315 (Pt 3): 883–8. PMID 8645172. Fulltext (subscription required)
- ^ University of Sydney lecture notes on the M2 receptors, 2005.
- ^ University of Sydney lecture notes on the M3 receptors, 2005.
- Dittman AH, Weber JP, Hinds TR, Choi EJ, Migeon JC, Nathanson NM, Storm DR. A novel mechanism for coupling of m4 muscarinic acetylcholine receptors to calmodulin-sensitive adenylyl cyclases: crossover from G protein-coupled inhibition to stimulation. Biochemistry. 1994, 33 (4): 943–51. PMID 8305442.
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