M2 and M3 Muscarinic Receptors Couple, Respectively, With Activation of Nonselective Cationic Channels and Potassium Channels in Intestinal Smooth Muscle Cells

The Japanese Journal of Pharmacology

Hidenori Ohashi¹  Takahisa Nakayama¹  Toshihiro Unno¹  Seiichi Komori¹ 

[1] Laboratory of Pharmacology, Department of Veterinary Science, Faculty of Agriculture, Gifu University

关键词: Carbachol;    Muscarinic receptor;    Smooth muscle;    Ca2+-activated K+ current;    Nonselective cationic current;   

DOI  :  10.1254/jjp.76.213

学科分类：药理学

来源: Nihon Yakuri Gakkai Henshuubu / Japanese Pharmacological Society

【 摘 要 】

References(24)Cited-By(20)Smooth muscle cells of guinea pig ileum express both M2 and M3 subtypes of muscarinic receptors. Under voltage clamp, activation of the muscarinic receptors with carbachol (CCh) induces Ca2+-activated K+ current (IK-Ca) and nonselective cationic current (Icat). Receptor subtypes mediating the current responses were characterized by using pirenzepine, AF-DX116, 4-DAMP and atropine, which have different profiles of the affinity constants for muscarinic receptor subtypes. The muscarinic antagonists inhibited either CCh-evoked IK-Ca or Icat with different potencies. Their relative potencies for IK-Ca and Icat inhibition resembled the relative affinity constants for M3 and M2 subtypes, respectively. Thus, the IK-Ca is mediated via the M3 subtype and the Icat via the M2 subtype.

【 授权许可】

Unknown