| Free-running rhythms of cocaine self-administration in rats held under constant lighting conditions. | |
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MedLine Citation:
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PMID: 20524799 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Using a discrete trials (DT) procedure, we have previously shown that rats exhibit variations in their pattern of cocaine self-administration relative to the time-of-day, often producing a daily rhythm of intake in which the majority of infusions occur during the dark phase of the 24 h light-dark cycle. We have sought to determine if cocaine self-administration demonstrates free-running circadian characteristics under constant-lighting conditions in the absence of external environmental cues. Rats self-administering cocaine (1.5 mg/kg/infusion) under a DT3 procedure (three trials/h) were kept in constant-dim (<2 lux, DIM) conditions, and the pattern of intake was analyzed for free-running behavior. We show that cocaine self-administration has a period length (tau) of 24.14 +/- 0.07 h in standard 12 h light:12 h dark conditions, which is maintained for at least five days in constant-dim conditions. With longer duration DIM exposure, cocaine self-administration free-runs with a tau of approximately 24.92 +/- 0.16 h. Exposure to constant-light conditions (1000 lux, LL) lengthened tau to 26.46 +/- 0.23 h; this was accompanied by a significant decrease in total cocaine self-administered during each period. The pattern of cocaine self-administration, at the dose and availability used in this experiment, is circadian and is likely generated by an endogenous central oscillator. The DT procedure is therefore a useful model to examine the substrates underlying the relationship between circadian rhythms and cocaine intake. |
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Authors:
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Caroline E Bass; Heiko T Jansen; David C S Roberts |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural |
Journal Detail:
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Title: Chronobiology international Volume: 27 ISSN: 1525-6073 ISO Abbreviation: Chronobiol. Int. Publication Date: 2010 May |
Date Detail:
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Created Date: 2010-06-07 Completed Date: 2010-09-10 Revised Date: 2012-02-15 |
Medline Journal Info:
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Nlm Unique ID: 8501362 Medline TA: Chronobiol Int Country: England |
Other Details:
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Languages: eng Pagination: 535-48 Citation Subset: IM |
Affiliation:
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Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Winston-Salem, North Carolina 27101, USA. cbass@wfubmc.edu |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Behavior, Animal Biological Clocks Circadian Rhythm Cocaine / administration & dosage* Light Lighting / methods* Male Photoperiod Rats Rats, Sprague-Dawley Running Self Administration / methods |
| Grant Support | |
ID/Acronym/Agency:
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DA023202/DA/NIDA NIH HHS; DA024763/DA/NIDA NIH HHS; DA14030/DA/NIDA NIH HHS; K01 DA024763-01A1/DA/NIDA NIH HHS; K01 DA024763-02/DA/NIDA NIH HHS; K01 DA024763-04/DA/NIDA NIH HHS; R01 DA014030-07/DA/NIDA NIH HHS; R01 DA014030-10/DA/NIDA NIH HHS; R01 DA023202-03/DA/NIDA NIH HHS |
| Chemical | |
Reg. No./Substance:
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50-36-2/Cocaine |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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