Blockers of potassium current and resting membrane potential in rat muscle fibers.
Rat diaphragm fibers were equilibrated for several hours in 150 mM KCl; when they were returned to 5 mM KCl the resting potential went back to its original level with a half time of 17 min. This repolarization was blocked by 5 mM BaCl2, a blocker of the inward rectifier K channel. On the other hand, 0.1 mM apamin and 0.02 mM glibenclamide which block the Ca-dependent and ATP sensitive K channels, respectively, and 0.1 mM 9-AC a blocker of the Cl- channel did not affect the repolarization. 5 mM barium decreased the K conductance measured under current-clamp conditions in diaphragm muscle fibers. The possible role of the inward rectifier system in the repolarization following return to normal [K]o is discussed.
Losavio
A S
AS
Instituto de Investigaciones Medicas A. Lanari, Buenos Aires, Argentina.
Delbono
O
O
Muchnik
S
S
Kotsias
B A
BA
D000818:Animals; D001030:Apamin / Q000494:pharmacology*; D001464:Barium / Q000494:pharmacology; D002413:Cations, Divalent; D005905:Glyburide / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects*; D009132:Muscles / Q000187:drug effects / Q000502:physiology*; D015221:Potassium Channels / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains
D002413:Cations, Divalent; D015221:Potassium Channels; D001030:Apamin; D001464:Barium; D005905:Glyburide