title: Tetrandrine inhibits both T and L calcium channel currents in ventricular cells.
abstract: Tetrandrine, a putative Ca2+ channel blocker, is extracted from the Chinese medicinal herb, Radix stephania tetrandrae. In the present study, the whole-cell version of the patch clamp technique was used to investigate the effects of tetrandrine on both T and L calcium channel currents in primary cultured neonatal rat ventricular cells. We show that tetrandrine inhibits both T and L calcium channel currents in ventricular cells. This inhibition of inward Ca2+ currents is concentration dependent and reversible. Tetrandrine does not shift the I-V relationship of the calcium currents. These results clearly demonstrate that tetrandrine acts as a calcium channel antagonist in ventricular cells. Previous data show that tetrandrine may be regarded as a wide-spectrum calcium channel antagonist.
mesh_terms: D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D044182:Benzylisoquinolines; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002478:Cells, Cultured; D006352:Heart Ventricles / Q000187:drug effects; D008564:Membrane Potentials / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism*; D009543:Nifedipine / Q000494:pharmacology; D051381:Rats
chemical_list: D000470:Alkaloids; D044182:Benzylisoquinolines; D002121:Calcium Channel Blockers; C009438:tetrandrine; D009543:Nifedipine; D002118:Calcium