Pflügers Archiv

, Volume 423, Issue 3, pp 167–172

Maxi K+ channels are stimulated by cyclic guanosine monophosphate-dependent protein kinase in canine coronary artery smooth muscle cells

Authors

  • Junichi Taniguchi
    • Department of Molecular PhysiologyNational Cardiovascular Center Research Institute
  • Ken -Ichi Furukawa
    • Department of Molecular PhysiologyNational Cardiovascular Center Research Institute
  • Munekazu Shigekawa
    • Department of Molecular PhysiologyNational Cardiovascular Center Research Institute
Heart, Circulation, Respiration and Blood; Environmental and Exercise Physiology

DOI: 10.1007/BF00374390

Cite this article as:
Taniguchi, J., Furukawa, K.-. & Shigekawa, M. Pflugers Arch. (1993) 423: 167. doi:10.1007/BF00374390

Abstract

By using a patch clamp technique, we examined the effect of cyclic guanosine monophosphate (cGMP)-dependent protein kinase (G kinase) on Ca2+-activated maxi K+ channels in canine coronary artery smooth muscle cells. Maxi K+ channels (274±4 pS in symmetrical 140 mM KCl at 24–26°C) were activated by cytoplasmic Ca2+ and were completely blocked by 100 nM charybdotoxin (CTX). G kinase (300 U/ml) added to the cytoplasmic face of the membrane patch shifted the voltage dependence of these channels by about 25 mV in the negative direction in the presence of 1 μM Ca2+, 50 μM cGMP and 1 mM magnesium adenosine triphosphate. At −50 mV and 1 μM Ca2+, G kinase treatment increased the mean number of open channels 4.5-fold compared with the control. α-Human atrial natriuretic peptide (ANP, 100 nM) reduced the isometric tension of coronary arterial rings elicited by 14 or 24 mM KCl, but failed to relax the artery contracted by 34 mM KCl. Addition of 100 nM CTX augmented tension development elicited by 24 mM KCl and totally prevented ANP from relaxing the arterial rings. These results indicate that G kinase-dependent protein phosphorylation activates maxi K+ channels in canine coronary smooth muscle, and further suggest that the G kinase-induced activation of maxi K+ channels may cause hyperpolarization and relaxation of coronary artery.

Key words

Maxi K+ channels cGMP-dependent protein kinase Canine coronary artery Atrial natriuretic peptide Patch clamp

Copyright information

© Springer-Verlag 1993