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

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Author(s)

Abstract

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 Ca<SUP>2+</SUP>-activated K<SUP>+</SUP> current (I<SUB>K-Ca</SUB>) and nonselective cationic current (I<SUB>cat</SUB>). 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 I<SUB>K-Ca</SUB> or I<SUB>cat</SUB> with different potencies. Their relative potencies for I<SUB>K-Ca</SUB> and I<SUB>cat</SUB> inhibition resembled the relative affinity constants for M3 and M2 subtypes, respectively. Thus, the I<SUB>K-Ca</SUB> is mediated via the M3 subtype and the I<SUB>cat</SUB> via the M2 subtype.

Journal

  • The Japanese Journal of Pharmacology

    The Japanese Journal of Pharmacology 76(2), 213-218, 1998-02

    The Japanese Pharmacological Society

References:  24

Cited by:  2

Codes

  • NII Article ID (NAID)
    10008191655
  • NII NACSIS-CAT ID (NCID)
    AA00691188
  • Text Lang
    ENG
  • Article Type
    Journal Article
  • ISSN
    00215198
  • NDL Article ID
    4416248
  • NDL Source Classification
    ZS51(科学技術--薬学)
  • NDL Call No.
    Z53-D199
  • Data Source
    CJP  CJPref  NDL  J-STAGE 
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