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Orexin A depolarises rat intergeniculate leaflet neurons through non‐selective cation channels
Author(s) -
PalusChramiec Katarzyna,
Chrobok Lukasz,
Kepczynski Mariusz,
Lewandowski Marian Henryk
Publication year - 2019
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/ejn.14394
Subject(s) - orexin , neuroscience , suprachiasmatic nucleus , excitatory postsynaptic potential , electrophysiology , biology , postsynaptic potential , patch clamp , ion channel , neuropeptide , hypothalamus , inhibitory postsynaptic potential , receptor , biochemistry
Abstract Orexins/hypocretins are hypothalamic neuropeptides that have a variety of functions, including maintenance of arousal, control over the sleep/wake cycle, reward and feeding. Accumulating evidence links orexins to the time‐keeping system with a documented action in the master clock—the suprachiasmatic nucleus. The intergeniculate leaflet ( IGL ) is a thalamic structure with the well‐known function of collecting photic and non‐photic cues to adjust the rhythm of the suprachiasmatic nucleus to changing environmental conditions. The IGL consists of GABA ergic neurons that are intrinsically active, even in slice preparations. Our previous studies revealed the excitatory postsynaptic effects of orexins on single IGL neurons, even though the ionic mechanism underlying this effect remained elusive. Therefore, in this study, we used patch clamp electrophysiology to identify the ions and distinct ion channels responsible for the observed depolarisations. The major finding of this article is that the orexin A‐evoked depolarisation of IGL neurons depends on non‐selective cation channels, implicating the orexinergic tone in establishing the basal firing rate in these cells. The data presented here strengthen the mutual connections between the time‐keeping and orexinergic systems.