title: Barium resistant potassium current in mammalian skeletal muscle following denervation.
abstract: Inward rectifier potassium channels are thought to be related to resting membrane potential and in innervated skeletal muscle they are specially sensitive to the blocking action of Ba2+ ions. After denervation other channels are known to become resistant to their blockers. We study the effect of Ba2+ upon the inward rectifier potassium channels after denervation. Rat extensor digitorum longus fibers were equilibrated for 150 minutes 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 35 minutes. This repolarization was blocked by 5 mM BaCl2 in innervated muscles and in muscles denervated for 7 days, but failed to do so after 14 days of denervation. Voltage-clamp experiments performed in lumbricalis denervated muscle showed a lack of effect of Ba2+ upon potassium current after 18 days of denervation. This results suggest that the inward rectifier potassium channels become resistant to Ba2+ ions after denervation, indicating a neural influence.
authors: Instituto de Investigaciones Medicas A. Lanari, Buenos Aires, Argentina.
authors: A S
authors: AS
authors: Losavio
authors: G C
authors: GC
authors: Bertran
authors: S
authors: S
authors: Muchnik
mesh_terms: D000818:Animals; D001464:Barium / Q000494:pharmacology*; D066298:In Vitro Techniques; D015640:Ion Channel Gating; D008564:Membrane Potentials; D009121:Muscle Denervation; D009132:Muscles / Q000502:physiology*; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000502:physiology*; D015221:Potassium Channels / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D015221:Potassium Channels; D001464:Barium; D011188:Potassium