The effect of R56865, a benzothiazolamine derivative, on the Na+ channel was studied using different methods (indirect: V(max) measurements; direct: Na+ current under voltage clamp conditions and single channel analysis) on different cardiac preparations (rabbit Purkinje fibres, guinea-pig papillary muscles and guinea-pig ventricular single cells). Agonistic effects were obtained when hyperpolarized holding potentials and low frequency stimulation were used, antagonistic effects when depolarized holding potentials (inactivation block) and high frequency stimulation (use-dependent block) were applied. Recovery from block was voltage-dependent, and faster at hyperpolarized potentials. Burst duration was markedly shortened in DPI (DPI 201-106)-treated patches. The relation between the effects on the Na+ channel and the anti-digitalis effects are discussed.
机构:
UNIV CALIF SAN FRANCISCO, SCH MED, DEPT PHARMACOL, SAN FRANCISCO, CA 94143 USAUNIV CALIF SAN FRANCISCO, SCH MED, DEPT PHARMACOL, SAN FRANCISCO, CA 94143 USA
HONDEGHEM, LM
KATZUNG, BG
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机构:
UNIV CALIF SAN FRANCISCO, SCH MED, DEPT PHARMACOL, SAN FRANCISCO, CA 94143 USAUNIV CALIF SAN FRANCISCO, SCH MED, DEPT PHARMACOL, SAN FRANCISCO, CA 94143 USA
机构:
UNIV CALIF SAN FRANCISCO, SCH MED, DEPT PHARMACOL, SAN FRANCISCO, CA 94143 USAUNIV CALIF SAN FRANCISCO, SCH MED, DEPT PHARMACOL, SAN FRANCISCO, CA 94143 USA
HONDEGHEM, LM
KATZUNG, BG
论文数: 0引用数: 0
h-index: 0
机构:
UNIV CALIF SAN FRANCISCO, SCH MED, DEPT PHARMACOL, SAN FRANCISCO, CA 94143 USAUNIV CALIF SAN FRANCISCO, SCH MED, DEPT PHARMACOL, SAN FRANCISCO, CA 94143 USA