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The serotonin inhibition of high‐voltage‐activated calcium currents is relieved by action potential‐like depolarizations in dissociated cholinergic nucleus basalis neurons of the guinea‐pig
Author(s) -
Williams Sylvain,
Serafin Mauro,
Mühlethaler Michel,
Bernheim Laurent
Publication year - 1998
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 - 10.1046/j.1460-9568.1998.00385.x
Subject(s) - basal forebrain , nucleus basalis , neuroscience , cholinergic , serotonin , depolarization , chemistry , voltage dependent calcium channel , cholinergic neuron , calcium , electrophysiology , endocrinology , biology , medicine , receptor , biochemistry , organic chemistry
The aim of the present study was to investigate whether the voltage‐dependent inhibition of calcium currents by serotonin 5‐HT 1A agonists can be alleviated (facilitated) by action potential‐like depolarizations. In dissociated cholinergic basal forebrain neurons using whole‐cell recordings, it is shown that a selective serotonin 5‐HT 1A agonist (8‐OH‐DPAT) predominantly blocks N‐type HVA calcium current, although a minor reduction of P‐type current was also observed. The inhibition may principally occur through G i ‐G o subtypes of G‐proteins because it was prevented by N‐ethylmaleimide, a substance known to block specifically pertussis‐sensitive G‐proteins. The inhibitory effect of 8‐OH‐DPAT on calcium currents is voltage‐dependent because it was alleviated by long‐lasting depolarizing prepulses. Interestingly, the inhibition could also be reversed by prepulses made‐up of action potential‐like depolarizations that were given at a frequency of 200 Hz. This observation may have important implications during periods of high‐frequency rhythmic bursts, a firing pattern that is prevalent in cholinergic basal forebrain neurons.