1982 Volume 18 Issue 5 Pages 339-345
Sakai, Y., Ichikawa, S., Yoshida, M., Oouchi, M. and Miyagawa, M. ATPase Activity and Calcium Uptake of Microsomes Isolated from Stomach Smooth Muscle after Exposure to Phospholipase C. Japanese J. Smooth Muscle Res., 1982, 18, (5), 339-345. ATPase activity and Ca2+ uptake were examined in microsomal membrane fractions isolated from guinea pig stomach smooth muscle which had been exposed to phospholipase C (PLC). Basal Mg2+-ATPase, Na+, K+-ATPase and Ca2+, Mg2+-ATP activities were inhibited in a time dependent manner by PLC treatment. There was positive correlatioon between each of these ATPase activities and total phospholipid content of the microsomal fraction. Phosphotidylcholine restored Ca2+, Mg2+-ATPase activity of the microsomal fraction isolated from the tissue which had been treated with PLC for 30min but not after 60min. Ca2+ uptake in the presence of ATP by microsomal fraction from tissue treated with PLC for 60min was significantly decreased. The results provide a cellular basis for the inhibitory effect of PLC on contractility of stomach smooth muscle.
