For the purpose of studying the properties of calcium channel, the effect of pH on the KCI induced Ca-uptake in the isolated porcine intestinal sarcolemmal vesicles, which were loaded with high KCI was investigated.
The obtained results were as follows;
1. Ca-uptake in the membrane of depolarized state by high KCI, compared with that of polarized state by low KCI in the medium was increased significantly(increased about 95.7% for 30 seconds, pH 7.4).
2. Ca-uptake in the membrane of predepolarized state by high KCI, compared with that of polarized state by low KCI was also increased significantly but less than that of depolarized state by high KCI (increased about 66.7% for 30 seconds, pH 7.4).
3. Influence of pH on the Ca-uptake of various membrane state was increased or decreased according to pH changes. Ca-uptake in the membranes of incubated at pH 6.0 was decreased about 48.5%, but increased about 10f and 36% at pH 8.0 and 9.0 respectively, compared with that incubated at pH 7.4.
4. KCI-induced Ca-uptake at the various pH conditions, was not inhibited by the pretreatment of diltiazem(10^(-6)M).
From the above results, it was concluded that KCI-induced Ca-uptake at the various pH conditions in the isolated sarcolemmal membranes, prepared from porcine intestinal smooth muscle, was not mediated through channels which are inhibited by organic Ca-antagonists.
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