urb-597 and Substance-Withdrawal-Syndrome

The endocannabinoid system is prominently implicated in the control of cocaine reinforcement due to its relevant role in synaptic plasticity and neurotransmitter modulation in the mesocorticolimbic system. The inhibition of fatty acid amide hydrolase (FAAH), and the resulting increase in anandamide and other N-acylethanolamines, represents a promising strategy for reducing drug seeking. In the present study, we aimed to assess the effects of the FAAH inhibitor URB597 (1 mg/kg) on crucial features of cocaine addictive-like behaviour in mice. Therefore, we tested the effects of URB597 on acquisition of cocaine (0.6 mg/kg/inf) self-administration, compulsive-like cocaine intake and cue-induced drug-seeking behaviour during withdrawal. URB597 reduced cocaine intake under conditioned punishment while having no impact on acquisition. This result was associated to increased cannabinoid receptor 1 gene expression in the ventral striatum and medium spiny neurons activation in the nucleus accumbens shell. Moreover, URB597 mitigated cue-induced drug-seeking behaviour during prolonged abstinence and prevented the withdrawal-induced increase in FAAH gene expression in the ventral striatum. In this case, URB597 decreased activation of medium spiny neurons in the nucleus accumbens core. Our findings evidence the prominent role of endocannabinoids in the development of cocaine addictive-like behaviours and support the potential of FAAH inhibition as a therapeutical target for the treatment of cocaine addiction.

Topics: Amidohydrolases; Animals; Cocaine-Related Disorders; Mice; Punishment; Substance Withdrawal Syndrome

Methamphetamine is an addictive stimulant that possesses toxicity in the brain when taken repeatedly or at higher doses. Methamphetamine neurotoxicity is associated with numerous forms of mental impairment, including depression and anxiety. Evidence has also demonstrated that the endocannabinoid system is involved in the regulation of anxiety and depression.. This study was designed to determine the involvement of the endocannabinoid system in anxiety- and depression-related behaviors in methamphetamine-withdrawal male NMRI mice.. The elevated plus maze and forced swim test were used to assess the level of anxiety and depression.. We found that methamphetamine (30 mg/kg, intraperitoneal) evoked depressive- and anxiogenic-like effects at 3 days post-administration. Injection of URB597 (5-10 ng/mouse, intracerebroventricular), 10 min before the test, prevented the emotional deficits induced by methamphetamine withdrawal. Moreover, the cannabinoid receptor type 1 antagonist AM251 (1 μg/mouse) or cannabinoid receptor type 2 antagonist AM630 (5 and 10 μg/mouse) suppressed the antidepressant activity in the methamphetamine-withdrawal mice treated with URB597. The transient receptor potential vanilloid 1 antagonist capsazepine (25 μg/mouse) prevented while capsazepine (100 μg/mouse) potentiated the antidepressant efficacy in the methamphetamine-withdrawal mice treated with URB597. The higher dose of AM630 and two higher doses of capsazepine had antidepressant efficacy, by themselves. Furthermore, capsazepine (50 μg/mouse) increased locomotion in the methamphetamine-withdrawal mice treated with URB597.. The results suggest that URB597 has a potential for preventing methamphetamine withdrawal-evoked anxiety and depression. Cannabinoid type 1 receptors, cannabinoid type 2 receptors and transient receptor potential vanilloid 1 differently affect depression-related behaviors in methamphetamine-withdrawal mice treated with URB597.

Topics: Amidohydrolases; Animals; Anxiety; Behavior, Animal; Benzamides; Cannabinoid Receptor Antagonists; Carbamates; Central Nervous System Stimulants; Depression; Disease Models, Animal; Endocannabinoids; Male; Methamphetamine; Mice; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Substance Withdrawal Syndrome; TRPV Cation Channels

The role of the endocannabinoid system in nicotine addiction is being increasingly acknowledged. Acute inhibition of anandamide (AEA) degradation efficiently reduces nicotine withdrawal-induced affective symptoms in rats and fatty acid amide hydrolase (FAAH), the degradation enzyme of AEA, has been proposed as a possible treatment against nicotine addiction. However, it is unclear whether chronic inhibition of AEA during nicotine abstinence will have beneficial or deleterious affective side-effects. Using a rat model of nicotine addiction, we found that, during abstinence, rats injected daily with a FAAH inhibitor (URB597) developed a depressive-like phenotype. Our results show that in the nicotine abstinent rats, URB597 induced low saccharin consumption, persistent immobility in the forced swim test and increased corticosterone levels in response to stress. In addition, URB597decreased CB1 receptor binding and activity in the habenula, a key structure in the control of nicotine-related emotional states. In contrast, non-treated abstinent rats showed increased CB1 receptor activity and behaviors comparable to controls. No FAAH inhibition-induced alterations were observed in animals that had a previous history of saline self-administration. Taken together, our results suggest that chronic FAAH inhibition prevents the homeostatic adaptations of habenular CB1 receptor function that are necessary for the recovery from nicotine dependence.

Topics: Amidohydrolases; Animals; Benzamides; Carbamates; Depression; Habenula; Male; Nicotine; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Self Administration; Substance Withdrawal Syndrome

Chronic morphine exposure causes tolerance and dependence. The cessation of morphine consumption induces a withdrawal syndrome that may involve cannabinoids and is characterized by undesirable psychological and physical signs. The present study examined whether augmentation of the endocannabinoid system by inhibition of fatty acid amide hydrolase could suppress the morphine withdrawal syndrome in morphine-addicted rats. Morphine dependency was induced by 7 consecutive days of morphine injection. The morphine-addicted rats received URB597 (1, 0.5, 0.3, 0.1, 0.03 mg/kg), a fatty acid amide hydrolase inhibitor, before the precipitation of morphine withdrawal syndromes by naloxone. Withdrawal symptoms including jumping, teeth chattering, paw tremor, wet dog shakes, face grooming, penis licking, standing, rearing, sniffing and percent of weight loss were recorded during 30 min after naloxone injection. The results showed that the morphine withdrawal precipitated rats had significantly more withdrawal symptoms than naive control rats and the administration of URB597 (all doses except 0.03 mg/kg) reduced most of the morphine withdrawal symptoms. We conclude that the administration of URB597 modulated morphine withdrawal symptoms. This finding shows that endocannabinoids interact with the opioid system during the morphine withdrawal period and that potentiation of the endogenous cannabinoid system by URB597 may be a new target strategy for the management of morphine addiction.

Topics: Amidohydrolases; Animals; Behavior, Animal; Benzamides; Cannabinoid Receptor Modulators; Carbamates; Humans; Male; Morphine Dependence; Random Allocation; Rats; Rats, Wistar; Substance Withdrawal Syndrome

Evidence shows that the endocannabinoid system modulates the addictive properties of nicotine. In the present study, we hypothesized that spontaneous withdrawal resulting from removal of chronically implanted transdermal nicotine patches is regulated by the endocannabinoid system. A 7-day nicotine dependence procedure (5.2 mg/rat/day) elicited occurrence of reliable nicotine abstinence symptoms in Wistar rats. Somatic and affective withdrawal signs were observed at 16 and 34 hours following removal of nicotine patches, respectively. Further behavioral manifestations including decrease in locomotor activity and increased weight gain also occurred during withdrawal. Expression of spontaneous nicotine withdrawal was accompanied by fluctuation in levels of the endocannabinoid anandamide (AEA) in several brain structures including the amygdala, the hippocampus, the hypothalamus and the prefrontal cortex. Conversely, levels of 2-arachidonoyl-sn-glycerol were not significantly altered. Pharmacological inhibition of fatty acid amide hydrolase (FAAH), the enzyme responsible for the intracellular degradation of AEA, by URB597 (0.1 and 0.3 mg/kg, i.p.), reduced withdrawal-induced anxiety as assessed by the elevated plus maze test and the shock-probe defensive burying paradigm, but did not prevent the occurrence of somatic signs. Together, the results indicate that pharmacological strategies aimed at enhancing endocannabinoid signaling may offer therapeutic advantages to treat the negative affective state produced by nicotine withdrawal, which is critical for the maintenance of tobacco use.

Topics: Acute Disease; Amidohydrolases; Animals; Anxiety; Arachidonic Acids; Benzamides; Brain; Cannabinoid Receptor Modulators; Carbamates; Cotinine; Endocannabinoids; Glycerides; Implants, Experimental; Locomotion; Male; Maze Learning; Nicotine; Polyunsaturated Alkamides; Rats; Rats, Wistar; Substance Withdrawal Syndrome; Tobacco Use Cessation Devices; Weight Gain

The potential of the fatty acid amide hydrolase (FAAH) inhibitor, URB597, to modify drug prime-induced reinstatement of morphine-induced conditioned floor preference or naloxone-precipitated morphine withdrawal-induced conditioned floor avoidance was evaluated. In Experiment 1, morphine-induced conditioned floor preference was established across 4 conditioning trials. Following extinction training (4 trials), rats were pretreated with URB597 or vehicle prior to a morphine prime or a saline prime. Morphine reinstated the previously extinguished floor preference, but URB597 did not modify the strength of the reinstated preference. In Experiment 2, naloxone-precipitated morphine withdrawal-induced conditioned floor avoidance was established across 2 conditioning trials. Following extinction training (14 trials), rats were pretreated with URB597 or vehicle prior to a saline prime or a morphine withdrawal prime. The morphine withdrawal prime reinstated the previously extinguished floor avoidance, but URB597 did not modify the strength of reinstated avoidance. These results suggest that under the conditions in which URB597 promotes extinction (e.g., Manwell et al. (2009)) it does not interfere with drug-induced reinstatement of either conditioned floor preference or avoidance. That is, although activation of the endocannabinoid (eCB) system promotes extinction of aversive learning, it may not prevent reinstatement of that aversion by re-exposure to the aversive treatment.

Topics: Amidohydrolases; Animals; Avoidance Learning; Benzamides; Cannabinoid Receptor Modulators; Carbamates; Conditioning, Classical; Endocannabinoids; Enzyme Inhibitors; Male; Morphine; Naloxone; Rats; Rats, Sprague-Dawley; Substance Withdrawal Syndrome

Abstinence symptoms in cannabis-dependent individuals are believed to contribute to the maintenance of regular marijuana use. However, there are currently no medications approved by the FDA to treat cannabis-related disorders. The only treatment currently shown consistently to alleviate cannabinoid withdrawal in both animals and humans is substitution therapy using the psychoactive constituent of marijuana, Delta(9)-tetrahydrocannabinol (THC). However, new genetic and pharmacological tools are available to increase endocannabinoid levels by targeting fatty acid amide hydrolase (FAAH) or monoacylglycerol lipase (MAGL), the enzymes responsible for the degradation of the endogenous cannabinoid ligands anandamide and 2-arachidonoylglycerol, respectively. In the present study, we investigated whether increasing endogenous cannabinoids levels, through the use of FAAH (-/-) mice as well as the FAAH inhibitor URB597 or the MAGL inhibitor JZL184, would reduce the intensity of withdrawal signs precipitated by the CB(1) receptor antagonist rimonabant in THC-dependent mice. Strikingly, acute administration of either URB597 or JZL184 significantly attenuated rimonabant-precipitated withdrawal signs in THC-dependent mice. In contrast, FAAH (-/-) mice showed identical withdrawal responses as wild-type mice under a variety of conditions, suggesting that the absence of this enzyme across the development of dependence and during rimonabant challenge does not affect withdrawal responses. Of importance, subchronic administration of URB597 did not lead to cannabinoid dependence and neither URB597 nor JZL184 impaired rotarod motor coordination. These results support the concept of targeting endocannabinoid metabolizing enzymes as a promising treatment for cannabis withdrawal.

Topics: Amidohydrolases; Animals; Benzamides; Benzodioxoles; Cannabinoid Receptor Modulators; Carbamates; Dronabinol; Endocannabinoids; Enzyme Inhibitors; Hallucinogens; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Monoacylglycerol Lipases; Motor Activity; Piperidines; Postural Balance; Psychomotor Performance; Pyrazoles; Rimonabant; Substance Withdrawal Syndrome

Converging evidence suggests that the endogenous cannabinoid (eCB) system is involved in extinction of learned behaviours. Using operant and classical conditioning procedures, the potential of the fatty acid amide (FAAH) inhibitor, URB-597, and the CB(1) antagonist/inverse agonist, SR141716, to promote and inhibit (respectively) extinction of learned responses previously motivated by either rewarding or aversive stimuli was investigated. In the operant conditioning procedure (Expt. 1), rats previously trained to lever press for sucrose reward were administered URB-597 (0.3 mg/kg) or the CB(1) antagonist/inverse agonist SR141716 (2.5 mg/kg) prior to each of three extinction trials. In the conditioned floor preference procedure (Expts 2a-d), rats trained to associate morphine with one of two distinctive floors were administered one of several doses of the CB(1) antagonist/inverse agonist, AM-251 (Expt 2a) or URB-597 (Expt 2b and 2d) prior to each extinction/test trial wherein a choice of both floors was presented and prior to forced exposure to each floor (Expt 2c). In the conditioned floor aversion procedure (Expt. 3), rats trained to associate a naloxone-precipitated morphine withdrawal with a floor cue were administered URB-597 or SR141716 prior to each of 24 extinction/testing trials. URB-597 did not promote and SR141716 did not reduce extinction rates for sucrose reward-induced operant responding (Expt. 1) or morphine-induced conditioned floor preference (Expts. 2a-d). In contrast, URB-597 facilitated, whereas SR141716 impaired, extinction of the conditioned floor aversion (Expt. 3). These data support previous reports that the eCB system selectively facilitates extinction of aversive memories. URB-597 may prove useful in targeting extinction of aversively motivated behaviours.

Topics: Amidohydrolases; Animals; Benzamides; Cannabinoid Receptor Modulators; Carbamates; Choice Behavior; Conditioning, Psychological; Dietary Sucrose; Extinction, Psychological; Female; Injections, Intraperitoneal; Injections, Subcutaneous; Male; Morphine; Morphine Dependence; Naloxone; Narcotic Antagonists; Narcotics; Piperidines; Pyrazoles; Rats; Rats, Long-Evans; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Reinforcement Schedule; Rimonabant; Species Specificity; Substance Withdrawal Syndrome