In:
European Journal of Neuroscience, Wiley, Vol. 42, No. 2 ( 2015-07), p. 1830-1838
Abstract:
The suprachiasmatic nucleus ( SCN ) contains a circadian clock that generates endogenous rhythmicity and entrains that rhythmicity with the day–night cycle. The neurochemical events that transduce photic input within the SCN and mediate entrainment by resetting the molecular clock have yet to be defined. Because GABA is contained in nearly all SCN neurons we tested the hypothesis that GABA serves as this signal in studies employing Syrian hamsters ( Mesocricetus auratus ). Activation of GABA A receptors was found to be necessary and sufficient for light to induce phase delays of the clock. Remarkably, the sustained activation of GABA A receptors for more than three consecutive hours was necessary to phase‐delay the clock. The duration of GABA A receptor activation required to induce phase delays would not have been predicted by either the prevalent theory of circadian entrainment or by expectations regarding the duration of ionotropic receptor activation necessary to produce functional responses. Taken together, these data identify a novel neurochemical mechanism essential for phase‐delaying the ‘master’ circadian clock within the SCN as well as identifying an unprecedented action of an amino acid neurotransmitter involving the sustained activation of ionotropic receptors.
Type of Medium:
Online Resource
ISSN:
0953-816X
,
1460-9568
DOI:
10.1111/ejn.2015.42.issue-2
Language:
English
Publisher:
Wiley
Publication Date:
2015
detail.hit.zdb_id:
2005178-5
SSG:
12
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