Translocation of protein kinase C by halothane in cholinergic cells

Protein kinase C (PKC) is a signal transducing enzyme that is an important regulator of multiple physiologic processes and a potential molecular target for volatile anaesthetic actions. However, the effects of these agents on PKC activity are not yet fully understood. Volatile anaesthetics increase intracellular calcium concentration ([Ca(2+)](i)) in a variety of cells, thus their effects on PKC activity may be indirect due to [Ca(2+)](i) increase. Alternatively, the anaesthetics could directly stimulate PKC activity. In order to distinguish these two possibilities in intact cells, we used a fully functional green fluorescent protein conjugated PKCbetaII (GFP-PKCbetaII) and confocal microscopy to evaluate the dynamic redistribution of PKC in living SN56 cells, a cholinergic cell line, in response to halothane. Halothane induced PKC translocation in SN56 cells transfected with GFP-PKCbetaII. This effect was not suppressed by dantrolene, a drug that blocks halothane-induced Ca(2+) release from intracellular stores in these cells. These findings indicate that halothane induces PKC translocation in SN56 cells independently of its ability to release calcium from internal stores.