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    Electrophysiological actions of orexins on rat suprachiasmatic neurons in vitro

    Brown, T.M. and Coogan, Andrew and Cutler, D.J. and Hughes, A.T. and Piggins, H.D. (2008) Electrophysiological actions of orexins on rat suprachiasmatic neurons in vitro. Neuroscience Letters, 448 (3). pp. 273-278. ISSN 03043940

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    The study of neural arousal mechanisms has been greatly aided by the discovery of the orexin peptides (orexin A and orexin B), the subsequent identification of the neurons that synthesize these peptides, their projections in the brain, and the distribution of orexin receptors in the central nervous system. Orexin neuron activation is partly controlled by circadian signals generated in the brain's main circadian pacemaker, the suprachiasmatic nuclei (SCN). The SCN clock is in turn reset by arousal-promoting stimuli and, intriguingly, orexin fibers and receptor expression are detected in the SCN region. It is unclear, however, if orexin can alter SCN neuronal activity. Here using a coronal brain slice preparation, we found that orexin A and orexin B (0.1–1 μM) elicited significant changes in the extracellularly recorded firing rate and firing pattern in ∼80% of rat SCN cells tested; the most common response was suppression of firing rate. Co-application of orexin A with a cocktail of ionotropic GABA and glutamate receptor antagonists did not alter the actions of this peptide on firing rate, but did change some its effects on firing pattern. We conclude that orexins can alter SCN neurophysiology and may influence the transmission of information through the SCN to other CNS regions.

    Item Type: Article
    Keywords: Hypocretin; Neurophysiology; Circadian; Arousal; Brain slice;
    Academic Unit: Assisting Living & Learning,ALL institute
    Faculty of Science and Engineering > Psychology
    Faculty of Science and Engineering > Research Institutes > Human Health Institute
    Item ID: 16464
    Identification Number:
    Depositing User: Dr. Andrew Coogan
    Date Deposited: 30 Aug 2022 15:13
    Journal or Publication Title: Neuroscience Letters
    Publisher: Elsevier
    Refereed: Yes
    Use Licence: This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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