- 作者: S. J. Hong; Wan-Wan Lin; C. C. Chang
- 作者服務機構: Department of Pharmacology, College of; Medicine, National Taiwan University, Taipei, Taiwan (ROC)
- 中文摘要: --
- 英文摘要: The effects of SK&F 96365, a blocker of the receptor-operated Ca2+ channel, on contractilities and the Na+ channel of mouse diaphragm were studied. SK&F 96365 (10-50 μM) reversibly inhibited twitches, tetanic contractions and muscle and nerve action potentials. The IC50 was 17-24μM . The inward Na+ current was suppressed and its recovery from inactivations delayed. Cro- tamine, a peptide toxin that binds to neurotoxin receptor site 3 of the muscle Na+ channel, enhanced the inhibitory effects of SK&F 96365 and reduced the IC50 to about 4μM. Veratridine had similar effects, although it was less effec- tive than crotamine. On the other hand, the crotamine-induced membrane depolarizations and spontaneous discharges of muscle action potentials were inhibited by SK&F 96365 noncompetitively. The inhibitory effects of tetrodo- toxin and tetracaine were additive with those of SK&F 96365 but were enhanced slightly by crotamine. The results suggested that SK&F 96365 acts on a distinct site and blocks the Na+ channel of excitable membranes at a concentration range that inhibits the receptor-operated calcium channel.
- 中文關鍵字: --
- 英文關鍵字: SK&F 96365; Crotamine; Calcium channel blocker; Local anesthetic; Sodium channel