Document Detail


Cannabinoids excite circadian clock neurons.
MedLine Citation:
PMID:  20668190     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Cannabinoids, the primary active agent in drugs of abuse such as marijuana and hashish, tend to generate a distorted sense of time. Here we study the effect of cannabinoids on the brain's circadian clock, the suprachiasmatic nucleus (SCN), using patch clamp and cell-attached electrophysiological recordings, RT-PCR, immunocytochemistry, and behavioral analysis. The SCN showed strong expression of the cannabinoid receptor CB1R, as detected with RT-PCR. SCN neurons, including those using GABA as a transmitter, and axons within the SCN, expressed CB1R immunoreactivity. Behaviorally, cannabinoids did not alter the endogenous free-running circadian rhythm in the mouse brain, but did attenuate the ability of the circadian clock to entrain to light zeitgebers. In the absence of light, infusion of the CB1R antagonist AM251 caused a modest phase shift, suggesting endocannabinoid modulation of clock timing. Interestingly, cannabinoids had no effect on glutamate release from the retinohypothalamic projection, suggesting a direct action of cannabinoids on the retinohypothalamic tract was unlikely to explain the inhibition of the phase shift. Within the SCN, cannabinoids were excitatory by a mechanism based on presynaptic CB1R attenuation of axonal GABA release. These data raise the possibility that the time dissociation described by cannabinoid users may result in part from altered circadian clock function and/or entrainment to environmental time cues.
Authors:
Claudio Acuna-Goycolea; Karl Obrietan; Anthony N van den Pol
Publication Detail:
Type:  In Vitro; Journal Article; Research Support, N.I.H., Extramural    
Journal Detail:
Title:  The Journal of neuroscience : the official journal of the Society for Neuroscience     Volume:  30     ISSN:  1529-2401     ISO Abbreviation:  J. Neurosci.     Publication Date:  2010 Jul 
Date Detail:
Created Date:  2010-07-29     Completed Date:  2010-08-20     Revised Date:  2011-09-26    
Medline Journal Info:
Nlm Unique ID:  8102140     Medline TA:  J Neurosci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  10061-6     Citation Subset:  IM    
Affiliation:
Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06520, USA.
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MeSH Terms
Descriptor/Qualifier:
6-Cyano-7-nitroquinoxaline-2,3-dione / pharmacology
Action Potentials / drug effects,  physiology
Adaptation, Ocular / drug effects,  physiology
Analgesics / pharmacology
Analysis of Variance
Animals
Animals, Newborn
Behavior, Animal / drug effects,  physiology
Benzoxazines / pharmacology
Biophysics / methods
Cannabinoids / genetics,  metabolism*
Circadian Rhythm / drug effects,  physiology*
Electric Stimulation / methods
Excitatory Amino Acid Antagonists / pharmacology
Excitatory Postsynaptic Potentials / drug effects
Gene Expression Regulation / drug effects,  physiology
Glutamate Decarboxylase / metabolism
Green Fluorescent Proteins / genetics
Male
Mice
Mice, Transgenic
Morpholines / pharmacology
Motor Activity / drug effects,  physiology
Naphthalenes / pharmacology
Neurons / drug effects,  physiology*
Patch-Clamp Techniques / methods
Piperidines / pharmacology
Pyrazoles / pharmacology
Receptor, Cannabinoid, CB1 / genetics,  metabolism
Suprachiasmatic Nucleus / cytology*
Tetrodotoxin
Valine / analogs & derivatives,  pharmacology
Grant Support
ID/Acronym/Agency:
MH62335/MH/NIMH NIH HHS; NS 067409/NS/NINDS NIH HHS; NS34887/NS/NINDS NIH HHS; NS48476/NS/NINDS NIH HHS; R01 DK084052-01A1/DK/NIDDK NIH HHS; R01 NS034887-13/NS/NINDS NIH HHS; R01 NS041454-09/NS/NINDS NIH HHS; R01 NS048476-07/NS/NINDS NIH HHS
Chemical
Reg. No./Substance:
0/AM 251; 0/Analgesics; 0/Benzoxazines; 0/Cannabinoids; 0/Excitatory Amino Acid Antagonists; 0/Morpholines; 0/Naphthalenes; 0/Piperidines; 0/Pyrazoles; 0/Receptor, Cannabinoid, CB1; 115066-14-3/6-Cyano-7-nitroquinoxaline-2,3-dione; 134959-51-6/Win 55212-2; 147336-22-9/Green Fluorescent Proteins; 4368-28-9/Tetrodotoxin; 7004-03-7/Valine; 76326-31-3/2-amino-5-phosphopentanoic acid; EC 4.1.1.15/Glutamate Decarboxylase; EC 4.1.1.15/glutamate decarboxylase 1
Comments/Corrections

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