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Dual role of calbindin‐D 28K in vesicular catecholamine release from mouse chromaffin cells
Author(s) -
Westerink R. H. S.,
Rook M. B.,
Beekwilder J. P.,
Wadman W. J.
Publication year - 2006
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.1471-4159.2006.04099.x
Subject(s) - exocytosis , calbindin , catecholamine , intracellular , synaptic vesicle , chromaffin cell , neurotransmitter , biophysics , chemistry , microbiology and biotechnology , biology , neurotransmission , vesicle , endocrinology , medicine , calcium , adrenal medulla , biochemistry , receptor , secretion , membrane , central nervous system , organic chemistry
Calbindin‐D 28K is suggested to play a postsynaptic role in neurotransmission and in the regulation of the intracellular Ca 2+ concentration. However, it is still unclear whether calbindin‐D 28K has a role in the regulation of exocytosis, either as Ca 2+ buffer or as Ca 2+ sensor. Amperometric recordings of catecholamine exocytosis from wild‐type and calbindin‐D 28K knockout mouse chromaffin cells reveal a strong reduction in the number of released vesicles, as well as in the amount of neurotransmitter released per fusion event in knockout cells. However, Ca 2+ current recordings and Ca 2+ imaging experiments, including video‐rate confocal laser scanning microscopy, revealed that the intracellular Ca 2+ dynamics are remarkably similar in wild‐type and knockout cells. The combined results demonstrate that calbindin‐D 28K plays an important and dual role in exocytosis, affecting both release frequency and quantal size, apparently without strong effects on intracellular Ca 2+ dynamics. Consequently, the possibility that calbindin‐D 28K functions not only as a Ca 2+ buffer but also as a modulator of vesicular catecholamine release is discussed.