Abstract
Effects of a K ionophore, lonomycin A (K+:Na+ = 6:1), on the action potential and contractile force in canine cardiac Purkinje fibers were examined. Lonomycin A increased the developed and resting tensions. The agent shortened the action potential, decreased the plateau height and suppressed the automaticity. In addition, lonomycin A also shortened the duration of the slow action potential response, and it shortened the action potential duration to about the same extent in the presence and absence of tetrodotoxin. In quiescent Purkinje fibers, lonomycin A decreased K content in both 1.8 mM Ca Tyrode's solution (contracture observed) and 0.18 mM Ca Tyrode's solution (contracture not observed). These results suggest that lonomycin A-induced changes in the action potential configuration of Purkinje fibers is mainly due to the increase in K conductance, and the increase is induced irrespective of the degree of the increased [Ca2+]i.
References
Aug 1, 1978·The Journal of Antibiotics·M Mitani, N Otake
Jan 1, 1976·Experientia·J M Gelles
Jan 24, 1975·Nature·G Isnberg
Apr 1, 1975·The American Journal of Physiology·K Shigenobu, N Sperelakis
May 1, 1985·Japanese Journal of Pharmacology·K TsuchidaS Chiba
Nov 1, 1967·Proceedings of the National Academy of Sciences of the United States of America·B C PressmanJ H Johnson
Aug 1, 1974·European Journal of Pharmacology·J A Schneider, N Sperelakis
Mar 1, 1973·The Journal of Physiology·T F McDonald, D P MacLeod
Sep 1, 1970·Circulation Research·A J Pappano
Mar 1, 1968·The Journal of Physiology·H Reuter, N Seitz
Feb 1, 1969·The Biochemical Journal·P J HendersonJ B Chappell
May 4, 1984·European Journal of Pharmacology·M S GaideA L Bassett
Mar 25, 1983·European Journal of Pharmacology·P A Molyvdas, N Sperelakis
Oct 1, 1982·Japanese Journal of Pharmacology·T Iijima
May 1, 1981·Journal of Pharmacobio-dynamics·K ShigenobuY Kasuya
Apr 27, 1956·The Journal of Physiology·S WEIDMANN
Citations
Nov 1, 1992·General Pharmacology·H SatohS Otomo
Nov 22, 2013·ISRN Pharmacology·Katsuharu TsuchidaYukiko Naito
Aug 26, 1999·General Pharmacology·H Satoh, K Tsuchida