CB1 receptor antagonism blocks stress-potentiated reinstatement of cocaine seeking in rats. Psychopharmacology (Berl) 2016 Jan;233(1):99-109
Date
10/13/2015Pubmed ID
26455361Pubmed Central ID
PMC4703460DOI
10.1007/s00213-015-4092-xScopus ID
2-s2.0-84953275278 (requires institutional sign-in at Scopus site) 32 CitationsAbstract
RATIONALE: Under some conditions, stress, rather than directly triggering cocaine seeking, potentiates reinstatement to other stimuli, including a subthreshold cocaine dose. The mechanisms responsible for stress-potentiated reinstatement are not well defined. Endocannabinoid signaling is increased by stress and regulates synaptic transmission in brain regions implicated in motivated behavior.
OBJECTIVES: The objective of this study was to test the hypothesis that cannabinoid type 1 receptor (CB1R) signaling is required for stress-potentiated reinstatement of cocaine seeking in rats.
METHODS: Following i.v. cocaine self-administration (2 h access/day) and extinction in male rats, footshock stress alone does not reinstate cocaine seeking but reinstatement is observed when footshock is followed by an injection of an otherwise subthreshold dose of cocaine (2.5 mg/kg, i.p.). CB1R involvement was tested by systemic administration of the CB1R antagonist AM251 (0, 1, or 3 mg/kg, i.p.) prior to testing for stress-potentiated reinstatement.
RESULTS: Stress-potentiated reinstatement was blocked by both 1 and 3 mg/kg AM251. By contrast, AM251 only attenuated food-reinforced lever pressing at the higher dose (i.e., 3 mg/kg) and did not affect locomotor activity at either dose tested. Neither high-dose cocaine-primed reinstatement (10 mg/kg, i.p.) nor footshock stress-triggered reinstatement following long-access cocaine self-administration (6 h access/day) was affected by AM251 pretreatment. Footshock stress increased concentrations of both endocannabinoids, N-arachidonylethanolamine and 2-arachidonoylglycerol, in regions of the prefrontal cortex.
CONCLUSIONS: These findings demonstrate that footshock stress increases prefrontal cortical endocannabinoids and stress-potentiated reinstatement is CB1R-dependent, suggesting that CB1R is a potential therapeutic target for relapse prevention, particularly in individuals whose cocaine use is stress-related.
Author List
McReynolds JR, Doncheck EM, Vranjkovic O, Ganzman GS, Baker DA, Hillard CJ, Mantsch JRAuthors
Cecilia J. Hillard PhD Associate Dean, Center Director, Professor in the Pharmacology and Toxicology department at Medical College of WisconsinJohn Mantsch PhD Chair, Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
AnimalsArachidonic Acids
Behavior, Addictive
Cocaine
Cocaine-Related Disorders
Endocannabinoids
Extinction, Psychological
Glycerides
Male
Piperidines
Pyrazoles
Rats
Rats, Sprague-Dawley
Receptor, Cannabinoid, CB1
Self Administration
Stress, Psychological
