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Further Characterization of Dopamine Release by Permeabilized PC 12 Cells
Author(s) -
AhnertHilger Gudrun,
Gratzl Manfred
Publication year - 1987
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1987.tb00959.x
Subject(s) - digitonin , dopamine , exocytosis , catecholamine , stimulation , biochemistry , biology , calcium , calmodulin , adrenal medulla , chemistry , biophysics , microbiology and biotechnology , endocrinology , enzyme , secretion , organic chemistry
Rat pheochromocytoma cells (PC 12) permeabilized with staphylococcal α‐toxin release [ 3 H]dopamine after addition of micromolar Ca 2+ . This does not require additional Mg 2+ ‐ATP (in contrast to bovine adrenal medullary chromaffin cells). We also observed Ca 2+ ‐dependent [ 3 H]‐dopamine release from digitonin‐permeabilized PC 12 cells. Permeabilization with α‐toxin or digitonin and stimulation of the cells were done consecutively to wash out endogenous Mg 2+ ‐ATP. During permeabilization, ATP was removed effectively from the cytoplasm by both agents but the cells released [ 3 H]dopamine in response to micromolar Ca 2+ alone. Replacement by chloride of glutamate, which could sustain mitochondrial ATP production in permeabilized cells, does not significantly alter catecholamine release induced by Ca 2+ . However, Mg 2+ without ATP augments the Ca 2+ ‐induced release. The release was unaltered by thiol‐, hydroxyl‐, or calmodulin‐interfering substances. Thus Mg 2+ ‐ATP, calmodulin, or proteins containing ‐SH or ‐OH groups are not necessary for exocytosis in permeabilized PC 12 cells.