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A store‐operated current (SOC) mediates oxytocin autocontrol in the developing rat hypothalamus
Author(s) -
Tobin Vicky,
Gouty LaurieAnne,
Moos Françoise C.,
Desarménien Michel G.
Publication year - 2006
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.1460-9568.2006.04935.x
Subject(s) - metabotropic receptor , neuroscience , metabotropic glutamate receptor , supraoptic nucleus , chemistry , t type calcium channel , acpd , oxytocin , voltage dependent calcium channel , medicine , endocrinology , biology , receptor , calcium , glutamate receptor , biochemistry , organic chemistry
Oxytocin (OT) and vasopressin (VP) autocontrol their secreting neurons in the supraoptic nucleus (SON) by modulating action potential firing through activation of specific metabotropic receptors. However, the mechanisms linking receptor activation to firing remain unknown. In almost all cell types, activation of plasma membrane metabotropic receptors triggers signalling cascades that induce mobilization of calcium from intracellular stores. In turn, emptying the calcium stores may evoke calcium influx through store‐operated channels (SOCs), the functions of which remain largely unknown in neurons. In this study, we show that these channels play a key role in the SON, at least in the response to OT. In isolated rat SON neurons, store depletion by thapsigargin induced an influx of calcium, demonstrating the presence of SOCs in these neurons. This calcium influx was specifically inhibited by 0.2 m m 1‐(2‐trifluoromethylphenyl‐)imidazole (TRIM). At 2 m m , this compound affected neither the resting electrophysiological properties nor the voltage‐dependant inward currents. In fresh slices, TRIM (2 m m ) did not affect the resting potential of SON neurons, action potential characteristics, spontaneous action potential firing or synaptic activity; this compound thus appears to be a specific blocker of SOCs in SON neurons. TRIM (0.2 m m ) specifically reduced the increase in action potential firing triggered by OT but did not affect the VP‐induced response. These observations demonstrate that store operated channels exist in hypothalamic neurons and specifically mediate the response to OT in the SON.