The Accumulation of Diacylglycerol and Activation of Protein Kinase C by Caffeine Treatment in Frog Skeletal Muscle.
Our previous work has shown that high K(+) exposure could induce an accumulation of diacylglycerol (DAG) and the activation of protein kinase C (PKC) in frog skeletal muscle. To elucidate its mechanism, the effect of caffeine on the pathway of DAG/PKC signal transduction was investigated. Caffeine could induce DAG accumulation and PKC activation in a dose- and time-dependent manner. The accumulation of DAG induced by caffeine was significantly different from that produced by high K(+) exposure, although the intracellular calcium was raised to a similar peak. In addition, differences in the activation of PKC were shown between caffeine and high K(+) exposure. These differences suggest that the myoplasmic calcium increase produced by high K(+) exposure is not a sole factor for the activation of DAG/PKC signal transduction in frog skeletal muscle, and the high K(+)-induced depolarization may play some roles.
Sun
Jun-Hui
JH
Shanghai Institute of Physiology, the Chinese Academy of Sciences, Shanghai 200031, China.
Zhu
Pei-Hong
PH