title: Voltage clamp study of the action of the new cardiotonic compound acrihellin on fast and slow inward currents in cardiac Purkinje fibres.
abstract: The action of 3 beta,5,14-trihydroxy-19-oxo-5 beta-bufa-20,22-dienolide-3-(3-methylcrotonate) (D 12316, acrihellin) on the fast and slow inward currents of sheep cardiac Purkinje fibres was analyzed by means of a conventional double microelectrode voltage clamp technique. Acrihellin diminished action potential duration and the plateau phase. Effective refractory periods were shortened in relation to the decrease in action potential duration. The upstroke velocity was slightly decreased; a systematic study of dV/dtmax, however, did not reveal any specific local anaesthetic side-effect of the drug. The decrease in the plateau phase of the action potential was due to a reduction in time-dependent slow inward current. The kinetics and the reversal potential of the slow inward current was not affected by acrihellin, but only the current voltage relationship, which was decreased.
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000779:Anesthetics, Local; D000818:Animals; D002018:Bufanolides / Q000494:pharmacology*; D002316:Cardiotonic Agents / Q000494:pharmacology*; D004594:Electrophysiology; D006329:Heart Conduction System / Q000187:drug effects*; D066298:In Vitro Techniques; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D011690:Purkinje Fibers / Q000187:drug effects*; D012756:Sheep
chemical_list: D000779:Anesthetics, Local; D002018:Bufanolides; D002316:Cardiotonic Agents; C039328:acrihellin