Mechanism of bilateral communication in the suprachiasmatic nucleus

Michel, Stephan, Marek, Roger, vanderLeest, Henk T., vanSteensel, Mariska J., Schwartz, William J., Colwell, Christopher S. and Meijer, Johanna H. (2013) Mechanism of bilateral communication in the suprachiasmatic nucleus. European Journal of Neuroscience, 37 6: 964-971. doi:10.1111/ejn.12109

Author Michel, Stephan
Marek, Roger
vanderLeest, Henk T.
vanSteensel, Mariska J.
Schwartz, William J.
Colwell, Christopher S.
Meijer, Johanna H.
Title Mechanism of bilateral communication in the suprachiasmatic nucleus
Journal name European Journal of Neuroscience   Check publisher's open access policy
ISSN 0953-816X
Publication date 2013-03
Year available 2013
Sub-type Article (original research)
DOI 10.1111/ejn.12109
Volume 37
Issue 6
Start page 964
End page 971
Total pages 8
Place of publication West Sussex, United Kingdom
Publisher Wiley-Blackwell
Collection year 2014
Language eng
Formatted abstract
The central circadian pacemaker of the suprachiasmatic nuclei (SCN) is a bilaterally symmetrical structure. Little is known about the physiological mechanisms underlying communication between the left and right SCN and yet the degree of synchronization between SCN neurons can have a critical impact on the properties of the circadian system. In this study, we used electrophysiological tools and calcium (Ca2+) imaging to examine the mechanisms underlying bilateral signaling in mouse SCN. Electrical stimulation of one SCN produced responses in the contralateral SCN with a short delay (approximately 5 ms) and Ca2+-dependence that are consistent with action potential-mediated chemical synaptic transmission. Patch-clamp recordings of stimulated cells revealed excitatory postsynaptic inward-currents (EPSCs), which were sufficient in magnitude to elicit action potentials. Electrical stimulation evoked tetrodotoxin-dependent Ca2+ transients in about 30% of all contralateral SCN neurons recorded. The responding neurons were widely distributed within the SCN with a highest density in the posterior SCN. EPSCs and Ca2+ responses were significantly reduced after application of a glutamate receptor antagonist. Application of antagonists for receptors of other candidate transmitters inhibited the Ca2+ responses in some of the cells but overall the impact of these antagonists was variable. In a functional assay, electrical stimulation of the SCN produced phase shifts in the circadian rhythm in the frequency of multiunit activity rhythm in the contralateral SCN. These phase shifts were blocked by a glutamate receptor antagonist. Taken together, these results implicate glutamate as a transmitter required for communication between the left and right SCN.
Keyword Circadian
Coupling pathways
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Queensland Brain Institute Publications
Official 2014 Collection
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Citation counts: TR Web of Science Citation Count  Cited 9 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 9 times in Scopus Article | Citations
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