Guinea-pig 결장뉴 K-경축에 미치는 칼슘 및 칼슘 억제제의 영향

Abstract

The effects of Ca" and its antagonists (verapamil, La') on the tension of K-induced contracture were studied in guinea-pig taenia coli. All experiments were performed in Tris-buffered Tyrode solution which was aerated with 100% 0, and kept at 35'C. The results obtained were as follows: 1. The K-contrature tension of muscle strips, both phasic and tonic components, increased in accordance with an increase of K+ concentration in the medium and tension reached maximum at 100 mM of K+. 2. During K-contracture induced by 100 mM of K+, tension of tonic component increased dosedependently in the range of 2-16 mM Calf while the phasic component was not altered in this range. In Ca" free solution, only phasic component of Kcontracture was produced and tonic component was disappeared. 3. After verapamil treatment, tension of tonic component of K-contracture decreased dose-dependently and muscle relaxed completely at the concentration of 1 mg/I, however, phasic component was only slightly suppressed. 4. When La' was added in the medium, the tonic component of K-contracture was markedly depressed. The results obtained in this experiment suggest that tension of tonic component of K-contracture was created by Ca-influx from extracellular Ca source, on the other hand, tension of phasic component was created by Ca-mobilization from intracellular Ca store.