title: Antagonism of cannabinoid 1 receptors reverses the anxiety-like behavior induced by central injections of corticotropin-releasing factor and cocaine withdrawal.
abstract: The endocannabinoid (eCB) system is an important regulator of the stress response and mediates several stress-related behaviors, including anxiety. Despite anatomical evidence that eCBs interact with the principle stress peptide, corticotropin-releasing factor (CRF), few data exist that address functional interactions between these systems. Accordingly, we examined the effects of the CB1 receptor antagonist, AM251, on behavioral anxiety induced by (1) exogenous CRF, and (2) withdrawal from chronic cocaine exposure (mediated by CRF). After behavioral testing, we collected blood and assessed plasma corticosterone levels. In Experiment 1, male Long-Evans rats were pretreated with AM251 (0, 10, 100, or 200 μg, i.c.v.), followed by CRF (0 or 0.5 μg, i.c.v.), before testing for anxiety-like behavior in the elevated plus maze (EPM). In Experiment 2, rats were exposed to cocaine (20 mg/kg, i.p.) or saline for 14 consecutive days. Forty-eight hours following cocaine exposure, rats were pretreated with AM251 (0, 10, or 100 μg, i.c.v.) and tested in the EPM. AM251 produced an anxiogenic response at the highest dose, but reversed the behavioral anxiety induced by CRF and withdrawal from chronic cocaine in a dose-dependent manner. AM251 also increased plasma corticosterone levels, but did so irrespective of CRF treatment or cocaine preexposure. Our findings suggest that the anxiogenic effects of CRF and cocaine withdrawal are mediated, at least in part, by CB1 receptor transmission, and provide evidence in support of eCB-CRF interactions that are independent of the hypothalamic-pituitary-adrenal axis.
authors.affiliation: Centre for the Neurobiology of Stress, University of Toronto Scarborough, Toronto, ON, Canada.
authors.forename: D A
authors.initials: DA
authors.lastname: Kupferschmidt
authors.forename: A E
authors.initials: AE
authors.lastname: Newman
authors.forename: R
authors.initials: R
authors.lastname: Boonstra
authors.forename: S
authors.initials: S
authors.lastname: Erb
mesh_terms: D000818:Animals; D001007:Anxiety / Q000097:blood / Q000139:chemically induced / Q000188:drug therapy*; D001522:Behavior, Animal / Q000187:drug effects; D003042:Cocaine / Q000009:adverse effects*; D003345:Corticosterone / Q000097:blood; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D018765:Dopamine Uptake Inhibitors / Q000009:adverse effects*; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects; D008297:Male; D010880:Piperidines / Q000494:pharmacology; D010913:Pituitary-Adrenal System / Q000187:drug effects; D011720:Pyrazoles / Q000494:pharmacology; D051381:Rats; D020318:Rats, Long-Evans; D043884:Receptor, Cannabinoid, CB1 / Q000037:antagonists & inhibitors*; D013375:Substance Withdrawal Syndrome / Q000188:drug therapy*
chemical_list: D018765:Dopamine Uptake Inhibitors; D010880:Piperidines; D011720:Pyrazoles; D043884:Receptor, Cannabinoid, CB1; C103505:AM 251; D003346:Corticotropin-Releasing Hormone; D003042:Cocaine; D003345:Corticosterone