title: Effect of sotalol on transmembrane ionic currents responsible for repolarization in cardiac ventricular myocytes from rabbit and guinea pig.
abstract: The effects of sotalol, a beta-adrenoceptor blocker and class III antiarrhythmic agent, on transmembrane ionic currents were examined in single rabbit and guinea pig ventricular myocytes using whole-cell voltage-clamp techniques. In neither of these species did 60 microM sotalol appreciably effect the inward rectifier, the transient outward or the inward calcium currents. In addition, sotalol did not elicit a slowly inactivating component of the sodium current as did 1 microgram/ml veratrine. In guinea pig ventricular myocytes, sotalol also significantly depressed the outward delayed rectifier current. An outward delayed rectifier current was not observed in rabbit ventricular myocytes examined at room temperature; and, under these conditions sotalol did not lengthen action potential duration. Sotalol induced lengthening of cardiac action potential duration can, therefore, be explained by depression the outward delayed rectifier current.
authors.affiliation: Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Ohio 45276.
authors.forename: A
authors.initials: A
authors.lastname: Varró
authors.forename: P P
authors.initials: PP
authors.lastname: Nánási
authors.forename: D A
authors.initials: DA
authors.lastname: Lathrop
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002104:Cadmium / Q000494:pharmacology; D019256:Cadmium Chloride; D002118:Calcium / Q000378:metabolism*; D004553:Electric Conductivity; D005260:Female; D006168:Guinea Pigs; D008297:Male; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism*; D011817:Rabbits; D012964:Sodium / Q000378:metabolism*; D013015:Sotalol / Q000494:pharmacology*
chemical_list: D002104:Cadmium; D012964:Sodium; D013015:Sotalol; D019256:Cadmium Chloride; D011188:Potassium; D002118:Calcium