胆嚢平滑筋の収縮に関連する諸因子,とくにカルシウムとの関連

概要

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The gall bladder of the guinea-pig was isolated and mounted in an organ bath perfusing with Krebs solution. The rectangular pulses through Ag plate electrodes were applied as an electrical stimulation. Drugs also used as a chemical stimulant. 1. The phasic contraction was evoked by the electrical stimulation (pulse width 5 msec, frequency 20 Hz, 30 Volt and 10 sec duration) . Even after 7 hours incubation in krebs solution, same response was obtained. 2. 1×10-7g/ml tetrodotoxin significantly depressed the evoked contraction by electrical stimulation, but no effect on the contracture was evoked by chemical stimulus. 3. The contractile response was affected with the temperature of the Krebs solution and also calcium concentration in the saline media. Adequate temperature for the evoked contraction was about 38°C and the concentration of calcium was 3-4 mM. 4. Forty mM KCl or 10-7g/ml acetylcholine chloride solution induced the phasic contraction following the tonic one. But these drug induced contracture was fade out, if the preparation was incubated in calcium free solution. It might be suggested that the calcium in muscle caused the tension development and that in saline media caused a maintenance of tonic contraction.