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Cuccurazzu B, Zamberletti E, Nazzaro C, Prini P, Trusel M, Grilli M, Parolaro D, Tonini R, Rubino T. Adult Cellular Neuroadaptations Induced by Adolescent THC Exposure in Female Rats Are Rescued by Enhancing Anandamide Signaling. Int J Neuropsychopharmacol 2018; 21:1014-1024. [PMID: 29982505 PMCID: PMC6209859 DOI: 10.1093/ijnp/pyy057] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 06/27/2018] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND In rodent models, chronic exposure to cannabis' psychoactive ingredient, Δ9-tetrahydrocannabinol, during adolescence leads to abnormal behavior in adulthood. In female rats, this maladaptive behavior is characterized by endophenotypes for depressive-like and psychotic-like disorders as well as cognitive deficits. We recently reported that most depressive-like behaviors triggered by adolescent Δ9-tetrahydrocannabinol exposure can be rescued by manipulating endocannabinoid signaling in adulthood with the anandamide-inactivating enzyme FAAH inhibitor, URB597. However, the molecular mechanisms underlying URB597's antidepressant-like properties remain to be established. METHODS Here we examined the impact of adult URB597 treatment on the cellular and functional neuroadaptations that occurred in the prefrontal cortex and dentate gyrus of the hippocampus upon Δ9-tetrahydrocannabinol during adolescence through biochemical, morphofunctional, and electrophysiological studies. RESULTS We found that the positive action of URB597 is associated with the rescue of Δ9-tetrahydrocannabinol-induced deficits in endocannabinoid-mediated signaling and synaptic plasticity in the prefrontal cortex and the recovery of functional neurogenesis in the dentate gyrus of the hippocampus. Moreover, the rescue property of URB597 on depressive-like behavior requires the activity of the CB1 cannabinoid receptor. CONCLUSIONS By providing novel insights into the cellular and molecular mechanisms of URB597 at defined cortical and hippocampal circuits, our results highlight that positive modulation of endocannabinoid-signaling could be a strategy for treating mood alterations secondary to adolescent cannabis use.
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Affiliation(s)
- Bruna Cuccurazzu
- Department of Pharmaceutical Sciences, University of Piemonte Orientale “A. Avogadro,” Novara, Italy
| | - Erica Zamberletti
- Department of Biotechnology and Life Sciences, and Neuroscience Center, University of Insubria, Busto Arsizio VA, Italy
| | - Cristiano Nazzaro
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia (IIT), Genova, Italy
| | - Pamela Prini
- Department of Biotechnology and Life Sciences, and Neuroscience Center, University of Insubria, Busto Arsizio VA, Italy
| | - Massimo Trusel
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia (IIT), Genova, Italy
| | - Mariagrazia Grilli
- Department of Pharmaceutical Sciences, University of Piemonte Orientale “A. Avogadro,” Novara, Italy
| | - Daniela Parolaro
- Department of Biotechnology and Life Sciences, and Neuroscience Center, University of Insubria, Busto Arsizio VA, Italy,Zardi Gori Foundation, Milan, Italy
| | - Raffaella Tonini
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia (IIT), Genova, Italy
| | - Tiziana Rubino
- Department of Biotechnology and Life Sciences, and Neuroscience Center, University of Insubria, Busto Arsizio VA, Italy,Correspondence: Tiziana Rubino, PhD, Department of Biotechnology and Life Sciences and Neuroscience Center, University of Insubria, via Manara 7, 21052 Busto Arsizio VA, Italy ()
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Aguilar DD, Giuffrida A, Lodge DJ. Adolescent Synthetic Cannabinoid Exposure Produces Enduring Changes in Dopamine Neuron Activity in a Rodent Model of Schizophrenia Susceptibility. Int J Neuropsychopharmacol 2018; 21:393-403. [PMID: 29329382 PMCID: PMC5887672 DOI: 10.1093/ijnp/pyy003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 01/05/2018] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Epidemiological studies recognize cannabis intake as a risk factor for schizophrenia, yet the majority of adolescents who use marijuana do not develop psychosis. Similarly, the abuse of synthetic cannabinoids poses a risk for psychosis. For these reasons, it is imperative to understand the effects of adolescent cannabinoid exposure in susceptible individuals. METHODS We recently developed a novel rodent model of schizophrenia susceptibility, the F2 methylazoxymethanol acetate rat, where only a proportion (~40%) of rats display a schizophrenia-like phenotype. Using this model, we examined the effects of adolescent synthetic cannabinoid exposure (0.2 mg/kg WIN55, 212-2, i.p.) or adolescent endocannabinoid upregulation (0.3 mg/kg URB597, i.p.) on dopamine neuron activity and amphetamine sensitivity in adulthood. RESULTS Adolescent synthetic cannabinoid exposure significantly increased the proportion of susceptible rats displaying a schizophrenia-like hyperdopaminergic phenotype after puberty without producing any observable alterations in control rats. Furthermore, this acquired phenotype appears to correspond with alterations in parvalbumin interneuron function within the hippocampus. Endocannabinoid upregulation during adolescence also increased the proportion of susceptible rats developing an increase in dopamine neuron activity; however, it did not alter the behavioral response to amphetamine, further emphasizing differences between exogenous and endogenous cannabinoids. CONCLUSIONS Taken together, these studies provide experimental evidence that adolescent synthetic cannabinoid exposure may contribute to psychosis in susceptible individuals.
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Affiliation(s)
- David D Aguilar
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, Texas,Correspondence: David D. Aguilar, PhD, Boston VA Medical Center, West Roxbury Research, Bldg 3, 2A115 1400 VFW Parkway, West Roxbury, MA, 02132 ()
| | - Andrea Giuffrida
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, Texas
| | - Daniel J Lodge
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, Texas
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Wills KL, Vemuri K, Kalmar A, Lee A, Limebeer CL, Makriyannis A, Parker LA. CB1 antagonism: interference with affective properties of acute naloxone-precipitated morphine withdrawal in rats. Psychopharmacology (Berl) 2014; 231:4291-300. [PMID: 24770676 DOI: 10.1007/s00213-014-3575-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 04/04/2014] [Indexed: 12/18/2022]
Abstract
RATIONALE Modulation of the endocannabinoid system has been found to interfere with opiate withdrawal. The potential of activation and blockade of the endocannabinoid system to prevent the aversive-affective state of naloxone-precipitated morphine withdrawal (MWD) was investigated in a one-trial conditioned place aversion (CPA) paradigm. OBJECTIVE CPA provides a sensitive measure of the motivational effects of acute MWD. The potential of the fatty acid amide hydrolase (FAAH) inhibitors, URB597 and PF-3845, the CB1 antagonist/inverse agonist, AM251, and the neutral CB1 antagonists, AM4113 and AM6527 (oral), to interfere with establishment of a MWD-induced CPA was investigated. As well, the potential of AM251 and AM4113 to interfere with reinstatement of a previously established MWD-induced CPA was investigated. MATERIALS AND METHODS Using a one-trial place conditioning paradigm, rats were administered naloxone (1 mg/kg, subcutaneous (s.c.)) 24 h after receiving a high dose of morphine (20 mg/kg, s.c.) and were placed on the conditioning floor. To determine the effect of each pretreatment drug on the establishment of the MWD-induced CPA, URB597 (0.3 mg/kg, intraperitoneally (i.p.)), PF-3845 (10 mg/kg, i.p.), AM251 (1 or 2.5 mg/kg, i.p.), AM4113 (1 or 2.5 mg/kg, i.p.), and AM6527 (5 mg/kg, oral) were administered prior to conditioning. RESULTS AM251 (2.5, but not 1 mg/k), AM4113, and AM6527, but not URB597 or PF-3845, interfered with the establishment of the MWD-induced CPA. AM251 and AM4113 did not prevent reinstatement of the CPA. CONCLUSIONS Neutral antagonism of the CB1 receptor reduces the aversive affective properties of morphine withdrawal.
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Abstract
The purpose of this review is to examine human and preclinical data that are relevant to the following hypotheses. The first hypothesis is that deficient CB1R-mediated signaling results in symptoms that mimic those seen in depression. The second hypothesis is that activation of CB1R-mediated signaling results in behavioral, endocrine and other effects that are similar to those produced by currently used antidepressants. The third hypothesis is that conventional antidepressant therapies act through enhanced CB1R mediated signaling. Together the available data indicate that activators of CB1R signaling, particularly inhibitors of fatty acid amide hydrolase, should be considered for clinical trials for the treatment of depression.
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MESH Headings
- Animals
- Antidepressive Agents/pharmacology
- Antidepressive Agents/therapeutic use
- Brain/drug effects
- Brain/enzymology
- Brain/metabolism
- Brain/pathology
- Cannabis
- Depressive Disorder, Major/drug therapy
- Depressive Disorder, Major/etiology
- Depressive Disorder, Major/genetics
- Depressive Disorder, Major/pathology
- Disease Models, Animal
- Endocannabinoids/genetics
- Endocannabinoids/metabolism
- Humans
- Magnetic Resonance Imaging
- Neurogenesis/drug effects
- Polymorphism, Genetic
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/metabolism
- Signal Transduction/drug effects
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Affiliation(s)
| | - Qing-song Liu
- Neuroscience Research Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226.
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Haller J, Goldberg SR, Pelczer KG, Aliczki M, Panlilio LV. The effects of anandamide signaling enhanced by the FAAH inhibitor URB597 on coping styles in rats. Psychopharmacology (Berl) 2013; 230:353-62. [PMID: 23743650 PMCID: PMC3830591 DOI: 10.1007/s00213-013-3161-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 05/20/2013] [Indexed: 12/15/2022]
Abstract
RATIONALE Coping styles are fundamental characteristics of behavior that affect susceptibility to, and resilience during, mental and physical illness. Shifts from passive to active coping are considered therapeutic goals in many stress-related disorders, but the neural control of coping is poorly understood. Based on earlier findings, we hypothesized that coping styles are influenced by endocannabinoids. OBJECTIVES Here, we tested whether FAAH inhibition by URB597 affects behaviors aimed at controlling a critical situation and the degree to which environmental stimuli influence behavior i.e., we studied the impact of URB597 on the two main attributes of coping styles. METHODS Rats were tested in the tail-pinch test of coping and in the elevated plus-maze test that was performed under highly divergent conditions. RESULTS Under the effects of URB597, rats focused their behavior more on the discomfort-inducing clamp in the tail-pinch test, i.e., they coped with the challenge more actively. In the elevated plus-maze, URB597-treated rats demonstrated an autonomous behavioral control by reducing both "wariness" induced by aversive conditions and "carelessness" resulting from favorable conditions. CONCLUSIONS URB597 treatment-induced behavioral changes indicated a shift towards active coping with challenges. This behavioral change appears compatible with the previously suggested role of endocannabinoids in emotional homeostasis. Albeit further studies are required to characterize the role of endocannabinoids in coping, these findings suggest that the enhancement of endocannabinoid signaling may become a therapeutic option in emotional disorders characterized by passive coping (e.g., anxiety and depression) and in physical diseases where active coping is therapeutically desirable.
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Affiliation(s)
- Jozsef Haller
- Department of Behavioral Neurobiology, Institute of Experimental Medicine, Budapest, Hungary,
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Okine BN, Norris LM, Woodhams S, Burston J, Patel A, Alexander SPH, Barrett DA, Kendall DA, Bennett AJ, Chapman V. Lack of effect of chronic pre-treatment with the FAAH inhibitor URB597 on inflammatory pain behaviour: evidence for plastic changes in the endocannabinoid system. Br J Pharmacol 2012; 167:627-40. [PMID: 22595021 PMCID: PMC3449266 DOI: 10.1111/j.1476-5381.2012.02028.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 04/19/2012] [Accepted: 04/25/2012] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND AND PURPOSE Elevating levels of endocannabinoids with inhibitors of fatty acid amide hydrolase (FAAH) is a major focus of pain research, purported to be a safer approach devoid of cannabinoid receptor-mediated side effects. Here, we have determined the effects of sustained pharmacological inhibition of FAAH on inflammatory pain behaviour and if pharmacological inhibition of FAAH was as effective as genetic deletion of FAAH on pain behaviour. EXPERIMENTAL APPROACH Effects of pre-treatment with a single dose, versus 4 day repeated dosing with the selective FAAH inhibitor, URB597 (i.p. 0.3 mg·kg⁻¹), on carrageenan-induced inflammatory pain behaviour and spinal pro-inflammatory gene induction were determined in rats. Effects of pain induction and of the drug treatments on levels of arachidonoyl ethanolamide (AEA), palmitoyl ethanolamide (PEA) and oleolyl ethanolamide (OEA) in the spinal cord were determined. KEY RESULTS Single, but not repeated, URB597 treatment significantly attenuated the development of inflammatory hyperalgesia (P < 0.001, vs. vehicle-treated animals). Neither mode of URB597 treatment altered levels of AEA, PEA and OEA in the hind paw, or carrageenan-induced paw oedema. Single URB597 treatment produced larger increases in AEA, PEA and OEA in the spinal cord, compared with those after repeated administration. Single and repeated URB597 treatment decreased levels of immunoreactive N-acylphosphatidylethanolamine phospholipase D (NAPE-PLD) in the spinal cord and attenuated carrageenan-induced spinal pro-inflammatory gene induction. CONCLUSION AND IMPLICATIONS Changes in the endocannabinoid system may contribute to the loss of analgesic effects following repeated administration of low dose URB597 in this model of inflammatory pain.
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Affiliation(s)
- Bright N Okine
- School of Biomedical Sciences, University of Nottingham, Queen's Medical CentreNottingham, UK
| | - Leonie M Norris
- School of Biomedical Sciences, University of Nottingham, Queen's Medical CentreNottingham, UK
- Centre for Analytical Bioscience, School of Pharmacy, University of NottinghamNottingham, UK
| | - Stephen Woodhams
- School of Biomedical Sciences, University of Nottingham, Queen's Medical CentreNottingham, UK
| | - James Burston
- School of Biomedical Sciences, University of Nottingham, Queen's Medical CentreNottingham, UK
- Arthritis Research UK Pain Centre, School of Biomedical Sciences, University of NottinghamNottingham, UK
| | - Annie Patel
- School of Biomedical Sciences, University of Nottingham, Queen's Medical CentreNottingham, UK
| | - Stephen PH Alexander
- School of Biomedical Sciences, University of Nottingham, Queen's Medical CentreNottingham, UK
| | - David A Barrett
- Centre for Analytical Bioscience, School of Pharmacy, University of NottinghamNottingham, UK
| | - David A Kendall
- School of Biomedical Sciences, University of Nottingham, Queen's Medical CentreNottingham, UK
| | - Andrew J Bennett
- School of Biomedical Sciences, University of Nottingham, Queen's Medical CentreNottingham, UK
| | - Victoria Chapman
- School of Biomedical Sciences, University of Nottingham, Queen's Medical CentreNottingham, UK
- Arthritis Research UK Pain Centre, School of Biomedical Sciences, University of NottinghamNottingham, UK
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Haller J, Barna I, Barsvari B, Gyimesi Pelczer K, Yasar S, Panlilio LV, Goldberg S. Interactions between environmental aversiveness and the anxiolytic effects of enhanced cannabinoid signaling by FAAH inhibition in rats. Psychopharmacology (Berl) 2009; 204:607-16. [PMID: 19259645 DOI: 10.1007/s00213-009-1494-7] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Accepted: 02/05/2009] [Indexed: 11/30/2022]
Abstract
RATIONALE Since the discovery of endogenous cannabinoid signaling, the number of studies exploring its role in health and disease has increased exponentially. Fatty acid amide hydrolase (FAAH), the enzyme responsible for degradation of the endocannabinoid anandamide, has emerged as a promising target for anxiety-related disorders. FAAH inhibitors (e.g., URB597) increase brain levels of anandamide and induce anxiolytic-like effects in rodents. Recent findings, however, questioned the efficacy of URB597 as an anxiolytic. OBJECTIVES We tested here the hypothesis that conflicting findings are due to variations in the stressfulness of experimental conditions employed in various studies. RESULTS We found that URB597 (0.1-0.3 mg/kg) did not produce anxiolytic effects when the aversiveness of testing procedures was minimized by handling rats daily before experimentation, by habituating them to the experimental room, or by employing low illumination during testing. In contrast, URB597 had robust anxiolytic effects when the aversiveness of the testing environment was increased by eliminating habituation to the experimental room or by employing bright lighting conditions. Unlike URB597, the benzodiazepine chlordiazepoxide (5 mg/kg) had anxiolytic effects under all testing conditions. The anxiolytic effects of URB597 were abolished by the cannabinoid CB1-receptor antagonist AM251, showing that they were mediated by CB1 receptors. Close inspection of experimental conditions employed in earlier reports suggests that conflicting findings with URB597 can be explained by different testing conditions, such as those manipulated in the present study. CONCLUSIONS Our findings show that FAAH inhibition does not affect anxiety under mildly stressful circumstances but protects against the anxiogenic effects of aversive stimuli.
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Justinova Z, Mangieri RA, Bortolato M, Chefer SI, Mukhin AG, Clapper JR, King AR, Redhi GH, Yasar S, Piomelli D, Goldberg SR. Fatty acid amide hydrolase inhibition heightens anandamide signaling without producing reinforcing effects in primates. Biol Psychiatry 2008; 64:930-7. [PMID: 18814866 DOI: 10.1016/j.biopsych.2008.08.008] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Revised: 07/08/2008] [Accepted: 08/04/2008] [Indexed: 11/21/2022]
Abstract
BACKGROUND CB(1) cannabinoid receptors in the brain are known to participate in the regulation of reward-based behaviors. However, the contribution of each of the endocannabinoid transmitters, anandamide and 2-arachidonoylglycerol (2-AG), to these behaviors remains undefined. To address this question, we assessed the effects of URB597, a selective anandamide deactivation inhibitor, as a reinforcer of drug-seeking and drug-taking behavior in squirrel monkeys. METHODS We investigated the reinforcing effects of the fatty acid amide hydrolase (FAAH) inhibitor URB597 in monkeys trained to intravenously self-administer Delta(9)-tetrahydrocannabinol (THC), anandamide, or cocaine and quantified brain endocannabinoid levels using liquid chromatography/mass spectrometry. We measured brain FAAH activity using an ex vivo enzyme assay. RESULTS URB597 (.3 mg/kg, intravenous) blocked FAAH activity and increased anandamide levels throughout the monkey brain. This effect was accompanied by a marked compensatory decrease in 2-AG levels. Monkeys did not self-administer URB597, and the drug did not promote reinstatement of extinguished drug-seeking behavior previously maintained by THC, anandamide, or cocaine. Pretreatment with URB597 did not modify self-administration of THC or cocaine, even though, as expected, it significantly potentiated anandamide self-administration. CONCLUSIONS In the monkey brain, the FAAH inhibitor URB597 increases anandamide levels while causing a compensatory down-regulation in 2-AG levels. These effects are accompanied by a striking lack of reinforcing properties, which distinguishes URB597 from direct-acting cannabinoid agonists such as THC. Our results reveal an unexpected functional heterogeneity within the endocannabinoid signaling system and suggest that FAAH inhibitors might be used therapeutically without risk of abuse or triggering of relapse to drug abuse.
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Trezza V, Vanderschuren LJMJ. Cannabinoid and opioid modulation of social play behavior in adolescent rats: differential behavioral mechanisms. Eur Neuropsychopharmacol 2008; 18:519-30. [PMID: 18434104 PMCID: PMC2490798 DOI: 10.1016/j.euroneuro.2008.03.001] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2007] [Revised: 02/01/2008] [Accepted: 03/04/2008] [Indexed: 12/01/2022]
Abstract
We have recently shown that the pharmacological mechanisms through which cannabinoid and opioid drugs influence social play behavior in adolescent rats can be partially dissociated. Here, we characterize the effects of the direct cannabinoid agonist WIN55,212-2, the indirect cannabinoid agonist URB597 and the opioid agonist morphine on social play at the behavioral level. By treating either one or both partners of the test dyad, we show that these drugs differentially affect play solicitation and play responsiveness. By testing these drugs in animals which were either familiar or unfamiliar to the test cage, we show that environmental factors differentially modulate the effects of cannabinoid and opioid drugs on social play. These results support and extend our previous findings suggesting that, although cannabinoid and opioid systems interact in the modulation of social play behavior in adolescent rats, they do so through partially dissociable behavioral and pharmacological mechanisms.
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Affiliation(s)
- Viviana Trezza
- Rudolf Magnus Institute of Neuroscience, Department of Neuroscience and Pharmacology, University Medical Center Utrecht, Utrecht, The Netherlands
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Rademacher DJ, Hillard CJ. Interactions between endocannabinoids and stress-induced decreased sensitivity to natural reward. Prog Neuropsychopharmacol Biol Psychiatry 2007; 31:633-41. [PMID: 17258369 PMCID: PMC1876712 DOI: 10.1016/j.pnpbp.2006.12.013] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Revised: 11/06/2006] [Accepted: 12/14/2006] [Indexed: 12/01/2022]
Abstract
Since endocannabinoids modulate reward processing and the stress response, we tested the hypothesis that endocannabinoids regulate stress-induced decreased sensitivity to natural reward. Restraint was used to produce stress-induced reductions in sucrose consumption and preference in male mice. Central cannabinoid receptor (CB(1)) signaling was modulated pharmacologically prior to the application of stress. The preference for sucrose over water was significantly decreased in mice exposed to restraint. Treatment of mice with a cannabinoid receptor agonist (CP55940) or fatty acid amide hydrolase inhibitor (URB597) attenuated, while the CB(1) receptor antagonist/inverse agonist, rimonabant (SR141716), enhanced, stress-induced decreases in sucrose preference. These data are consistent with a tonically active, stress-inhibitory role for the CB(1) receptor. Mice treated with 10 daily episodes of restraint showed reduced sucrose preference that was unaffected by CP55940 and URB597. However, rimonabant produced a greater reduction in sucrose preference on day 10 compared to day 1. These data suggest that on day 10, endocannabinoid signaling is maximally activated and essential for reward sensitivity. The findings of the present study indicate that the CB(1)/endocannabinoid signaling system is an important allostatic mediator that both modulates the responses of mice to stress and is itself modulated by stress.
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Affiliation(s)
- David J Rademacher
- Medical College of Wisconsin, Department of Pharmacology and Toxicology, 8701 Watertown Plank Road, Milwaukee, WI 53226 USA.
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Gobbi G, Bambico FR, Mangieri R, Bortolato M, Campolongo P, Solinas M, Cassano T, Morgese MG, Debonnel G, Duranti A, Tontini A, Tarzia G, Mor M, Trezza V, Goldberg SR, Cuomo V, Piomelli D. Antidepressant-like activity and modulation of brain monoaminergic transmission by blockade of anandamide hydrolysis. Proc Natl Acad Sci U S A 2005; 102:18620-5. [PMID: 16352709 PMCID: PMC1317988 DOI: 10.1073/pnas.0509591102] [Citation(s) in RCA: 510] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Indexed: 11/18/2022] Open
Abstract
Although anecdotal reports suggest that cannabis may be used to alleviate symptoms of depression, the psychotropic effects and abuse liability of this drug prevent its therapeutic application. The active constituent of cannabis, delta9-tetrahydrocannabinol, acts by binding to brain CB1 cannabinoid receptors, but an alternative approach might be to develop agents that amplify the actions of endogenous cannabinoids by blocking their deactivation. Here, we show that URB597, a selective inhibitor of the enzyme fatty-acid amide hydrolase, which catalyzes the intracellular hydrolysis of the endocannabinoid anandamide, exerts potent antidepressant-like effects in the mouse tail-suspension test and the rat forced-swim test. Moreover, URB597 increases firing activity of serotonergic neurons in the dorsal raphe nucleus and noradrenergic neurons in the nucleus locus ceruleus. These actions are prevented by the CB1 antagonist rimonabant, are accompanied by increased brain anandamide levels, and are maintained upon repeated URB597 administration. Unlike direct CB1 agonists, URB597 does not exert rewarding effects in the conditioned place preference test or produce generalization to the discriminative effects of delta9-tetrahydrocannabinol in rats. The findings support a role for anandamide in mood regulation and point to fatty-acid amide hydrolase as a previously uncharacterized target for antidepressant drugs.
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Affiliation(s)
- G Gobbi
- Department of Psychiatry, McGill University, Montréal, QC, Canada H1N 3V2
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