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Activation of P‐type calcium channel regulates a unique thapsigargin‐sensitive calcium pool in embryonic motoneurons
Author(s) -
Scamps Frédérique,
Roig Anne,
Boukhaddaoui Hassan,
André Sylvain,
Puech Sylvie,
Valmier Jean
Publication year - 2004
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.0953-816x.2004.03196.x
Subject(s) - thapsigargin , cyclopiazonic acid , depolarization , ryanodine receptor , microbiology and biotechnology , endoplasmic reticulum , voltage dependent calcium channel , t type calcium channel , biophysics , calcium , biology , chemistry , intracellular , voltage gated ion channel , r type calcium channel , calcium channel , inositol , calcium signaling , ion channel , biochemistry , receptor , organic chemistry
By regulating voltage‐dependent Ca 2+ influx and intracellular Ca 2+ homeostasis, electrical activity plays a central role in motoneuron development. Dissociated cultures of purified embryonic rat motoneurons were used to explore the molecular mechanisms by which Ca 2+ influx control [Ca 2+ ] i transients in these neurons. Thapsigargin (250 n m ) and cyclopiazonic acid (10 µ m ), which deplete Ca 2+ stores in the endoplasmic reticulum, decrease by 30% the depolarization‐induced [Ca 2+ ] i transients in motoneurons without affecting voltage‐activated calcium currents. This thapsigargin‐sensitive intracellular Ca 2+ pool differs from other previous described Ca 2+ stores that are sensitive to ryanodine or caffeine, inositol triphosphate, insulin and from mitochondrial Ca 2+ pools. Thapsigargin affected the Ca v 2.1 P‐type Ca 2+ channel component of the depolarization‐induced [Ca 2+ ] i transient in motoneurons but spared [Ca 2+ ] i transient induced by Ca v 1 L‐type and Ca v 2.2 N‐type Ca 2+ channel components, suggesting a close functional relationship between Ca v 2.1 subunit and this unique thapsigargin‐sensitive Ca 2+ store. Altogether the present results demonstrate a new pathway, used by embryonic motoneurons, to regulate Ca 2+ signalling through voltage‐activated (Ca v 2.1) Ca 2+ channels.