Effect of cromakalim on smooth muscle cells of guinea-pig taenia caeci.
Cromakalim caused hyperpolarization and reduction of the electrotonic potential in a concentration-dependent manner in smooth muscle cells of guinea-pig taenia caeci. There was a relatively constant change in the electrotonic potential under calcium-free, low-sodium and low-chloride conditions in the presence of cromakalim as compared to control conditions with Krebs solutiuon. The effect of cromakalin (10(-5) M) was inhibited by glibenclamide (5 X 10(-5) M). These results indicate that cromakalim specifically promotes potassium efflux in smooth muscle cells of the guinea-pig taenia caeci via glibenclamide-sensitive potassium channels, to cause hyperpolarization, suppression of spike activity and relaxation.
den Hertog
A
A
Department of Pharmacology/Clinical Pharmacology, University of Groningen, The Netherlands.
Van den Akker
J
J
Nelemans
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A
D000818:Animals; D001578:Benzopyrans / Q000494:pharmacology*; D002432:Cecum / Q000187:drug effects; D019806:Cromakalim; D004594:Electrophysiology; D005260:Female; D005905:Glyburide / Q000494:pharmacology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects*; D010276:Parasympatholytics / Q000494:pharmacology*; D011758:Pyrroles / Q000494:pharmacology*
D001578:Benzopyrans; D010276:Parasympatholytics; D011758:Pyrroles; D019806:Cromakalim; D005905:Glyburide