Document Detail


Mechanism of bilateral communication in the suprachiasmatic nucleus.
MedLine Citation:
PMID:  23311402     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
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 (Ca(2+) ) 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 Ca(2+) -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 Ca(2+) 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 Ca(2+) responses were significantly reduced after application of a glutamate receptor antagonist. Application of antagonists for receptors of other candidate transmitters inhibited the Ca(2+) 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.
Authors:
Stephan Michel; Roger Marek; Henk T Vanderleest; Mariska J Vansteensel; William J Schwartz; Christopher S Colwell; Johanna H Meijer
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2013-1-14
Journal Detail:
Title:  The European journal of neuroscience     Volume:  -     ISSN:  1460-9568     ISO Abbreviation:  Eur. J. Neurosci.     Publication Date:  2013 Jan 
Date Detail:
Created Date:  2013-1-14     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8918110     Medline TA:  Eur J Neurosci     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
© 2013 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.
Affiliation:
Laboratory for Neurophysiology, Department of Molecular Cell Biology, Leiden University Medical Center, LUMC PZ S5-P, PO 9600, 2300 RC, Leiden, The Netherlands.
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