Spatio-temporal regulation of neurotransmitter release by PKC; studies in adrenal chromaffin cells.
Activation of protein kinase C (PKC) seems to promote vesicle recruitment to the release-ready state prior to Ca2+ -triggered fusion in chromaffin cells. To understand spatio-temporal regulation of vesicle recruitment by PKC, we studied the effects of a phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA), on the vesicle movements in living chromaffin cells by imaging with a fluorescence microscope-cooled CCD system. About 60 approximately 80% of the chromaffin vesicles showed a rapid movement, about 20% showed a moderate movement, and the rest showed slow/no movement in resting and post-stimulation. The vesicles with slow/no movement increased to 40% upon a depolarizing stimulation, and TPA increased this population to about 70%. TPA treatment, in addition, increased the number of visible chromaffin vesicles beneath the plasma membrane, suggesting that the potentiation of vesicle recruitment by PKC involves a substantial increase in the subplasmalemmal distribution of vesicles.
Kumakura
Konosuke
K
Life Science Institute, Sophia University, Tokyo, Japan. kumakura@hoffman.cc.sophia.ac.jp
Sasakawa
Nobuyiki
N
Murayama
Norie
N
Ohara-Imaizumi
Mica
M
D000311:Adrenal Glands / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D019439:Chromaffin Cells / Q000187:drug effects / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D005089:Exocytosis / Q000187:drug effects / Q000502:physiology; D006801:Humans; D018377:Neurotransmitter Agents / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism*; D013572:Synaptic Vesicles / Q000187:drug effects / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D018377:Neurotransmitter Agents; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate