Dihydropyridine derivatives prolong the open state of Ca channels in cultured cardiac cells.
AUTOR(ES)
Kokubun, S
RESUMO
The dihydropyridine derivatives CGP 28392 and BAY K 8644 exert a strong positive inotropic effect in mammalian cardiac muscle, presumably by increasing Ca influx during the action potential. Analysis of the drug effects at the level of single Ca channels by means of the patch-clamp method revealed complicated changes in the kinetics of channel gating. The prevailing effect is a prolongation of the mean open time of Ca channels. In addition, the intervals between channel openings can be slightly prolonged. Ensemble averages of single-channel traces showed a concentration-dependent increase in the mean current amplitude by the drugs. In contrast to beta-adrenoceptor agonists, the increase in Ca current by the dihydropyridine derivatives is not associated with an increase in the intracellular cyclic AMP level.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=391583Documentos Relacionados
- Sodium channels in cultured cardiac cells.
- Inactivating and non-inactivating dihydropyridine-sensitive Ca2+ channels in mouse cerebellar granule cells.
- Inactivation of the cardiac Na+ channels in guinea-pig ventricular cells through the open state.
- Inactivation of the cardiac Na+ channels in guinea-pig ventricular cells through the open state
- Tetrodotoxin block of single germitrine-activated sodium channels in cultured rat cardiac cells.
