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cAMP directly facilitates Ca‐induced exocytosis in bovine lactotrophs
Author(s) -
Sikdar Sujit K.,
Zorec Robert,
Mason William T.
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)81072-v
Subject(s) - exocytosis , intracellular , membrane , biophysics , patch clamp , cytosol , secretion , conductance , chemistry , voltage clamp , membrane potential , microbiology and biotechnology , biology , biochemistry , enzyme , receptor , mathematics , combinatorics
We have used the whole cell patch clamp technique on single prolactin‐secreting bovine lactotrophs to measure plasma membrane capacitance ( C m ), an index of membrane surface area, under voltage‐clamp during cytosol dialysis with Ca and cAMP. cAMP increased the magnitude and rate of Ca‐induced exocytosis ( C m increase) without affecting membrane conductance; however, cAMP had no detectable effect on C m when intracellular Ca was low. We thus report new evidence that cAMP can facilitate Ca‐induced secretion in a synergistic fashion, by acting directly on the secretory apparatus, independently of membrane conductance activation.