Block effects of IHC-72 on calcium current in single guinea pig cardiac myocytes.
Block of the calcium current by IHC-72 in single ventricular myocytes isolated from guinea pig was studied by using the whole-cell patch clamp technique. IHC-72 in micromolar concentrations depressed the calcium current in a concentration-dependent manner, with an IC50 of 0.06 +/- 0.02 mcmol/l. After application of IHC-72 the peak calcium current began to decrease within 1 min and reached a steady state within 10 min. The current-voltage relationship for the calcium current peak was not changed by IHC-72, but the amplitude was significantly suppressed. Although IHC-72 did not alter the time course of inactivation of the calcium current, it shifted its steady state.
Ji
G J
GJ
Department of Pharmacology, Beijing Medical College of PLA, People's Republic of China.
Zhang
J Z
JZ
D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004492:Edetic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D004594:Electrophysiology; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects*; D066298:In Vitro Techniques; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D009861:Onium Compounds / Q000494:pharmacology*
D000889:Anti-Arrhythmia Agents; D002121:Calcium Channel Blockers; D009861:Onium Compounds; C077594:3,6-dimethylaminodibenzopyridonium edetate; D004492:Edetic Acid