Effects of halothane on membrane potentials and membrane ionic currents in single bullfrog atrial cells.
Halothane exerts negative inotropic and negative chronotropic actions on the isolated heart in experimental animals. In order to assess directly the actions of halothane in myocardium, we studied the effects of halothane on membrane potentials and transmembrane ionic currents in single isolated frog atrial cells obtained by the enzymatic dissociation method. The results show: (a) that the action potential is prolonged and its plateau phase and overshoot are depressed, but the resting potential remains unchanged; (b) that there is a significant inhibition of a time- and voltage-dependent outward K+ current and a slow inward Ca2+ current, with a slight decrease of a fast inward Na+ current following halothane (1.0-4.0%) application; and that halothane has no effect on another K+ current, time-independent current.
Hirota
K
K
Department of Anesthesiology, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Japan.
Ito
Y
Y
Momose
Y
Y
D000818:Animals; D003864:Depression, Chemical; D006221:Halothane / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects*; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects*; D008564:Membrane Potentials / Q000187:drug effects*; D009200:Myocardial Contraction / Q000187:drug effects*; D011892:Rana catesbeiana
D007473:Ion Channels; D006221:Halothane