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Nesfatin‐1 does not influence intracellular calcium concentrations in neurons of the nucleus of the solitary tract or the paraventricular nucleus
Author(s) -
Mimee Andrea,
Ferguson Alastair V.
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.1123.2
Subject(s) - solitary tract , nucleus , intracellular , chemistry , calcium in biology , electrophysiology , patch clamp , calcium , endocrinology , medicine , neuron , biophysics , calcium imaging , neuropeptide , neuroscience , biology , receptor , biochemistry
Nesfatin‐1 (nes‐1) is a neuropeptide which exerts potent effects on food intake, cardiovascular parameters, and the stress axis. Immunohistochemical studies have shown expression of nes‐1 in the nucleus of the solitary tract (NTS) and paraventricular nucleus (PVN). To date there is minimal data describing the mechanism of action of nes‐1 in the brain. Using whole cell patch clamp recordings, we have previously shown bath applied nes‐1(10 nM) influences the membrane potential of 63% of NTS and 71% of PVN neurons. Here, as a first step in investigating the mechanism of nes‐1 actions, we examined the effect of nes‐1 on intracellular Ca 2+ concentrations ([Ca 2+ ] i ) in dissociated NTS and PVN neurons loaded with the Ca 2+ indicator Fura2‐AM. Bath application of nes‐ 1 at 10 and 100 nM increased [Ca 2+ ] i in 4% ( n =75) and 3% ( n =84) of NTS neurons, respectively, as assessed by a minimum 20% increase in the ratiometric value of [Ca 2+ ] i . Furthermore, 9% ( n =125) of PVN neurons showed an increase in [Ca 2+ ] i in response to 10 nM nes‐1. Our findings show nes‐1 does not influence [Ca 2+ ] i in NTS or PVN neurons. A large discrepancy also exists in the proportion of neurons reported as responsive to nes‐1 in our electrophysiological vs calcium imaging experiments, suggesting studies of nes‐1 effects on [Ca 2+ ] i may not be an appropriate method of evaluating neuronal nes‐1 activation patterns or mechanisms of action. Funding: NSERC, FQRNT, HSFO.