Comparison of exocytotic mechanisms between acetylcholine- and catecholamine-containing vesicles in rat pheochromocytoma cells.
The molecular mechanisms of exocytosis from two types of secretory organelles, synaptic-like microvesicles and secretory vesicles, were compared by measuring acetylcholine (ACh) and catecholamine (CA) release from a newly isolated PC12 subclone, PC12-C3 which contains a high level of Ach. Digitonin-permeabilized PC12-C3 cells released both transmitters with similar Ca(2+)-dependency. Ca(2+)-evoked Ach and CA release from permeabilized cells were increased in the presence of MgATP, suggesting the existence of a MgATP-dependent priming step prior to the Ca(2+)-triggered fusion step in both ACh release and CA release. The non-hydrolyzable analogue of GTP guanosine 5'-(gamma-thio)triphosphate (GTP gamma S), produced both ACh and CA release from permeabilized cells in the absence of Ca2+. Pretreatment with a phorbol ester which activates protein kinase C, potentiated depolarization-induced ACh and CA release from unpermeabilized cells. These results indicated that exocytosis from two distinct vesicle populations are mediated by the same basic molecular mechanisms.
Nishiki
T
T
Mitsubishi Kasei Institute of Life Sciences, Tokyo, Japan.
Shoji-Kasai
Y
Y
Sekiguchi
M
M
Iwasaki
S
S
Kumakura
K
K
Takahashi
M
M
D000109:Acetylcholine / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002395:Catecholamines / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D005089:Exocytosis; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D016716:PC12 Cells; D011188:Potassium / Q000378:metabolism; D051381:Rats; D013572:Synaptic Vesicles / Q000187:drug effects / Q000378:metabolism*
D002395:Catecholamines; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D000255:Adenosine Triphosphate; D000109:Acetylcholine; D011188:Potassium; D002118:Calcium