ABSTRACT
Introduction: Male reproduction is under the control of the hypothalamus-pituitary-gonadal (HPG) axis. The endocannabinoid system (ECS) and the kisspeptin system (KS) are two major signaling systems in the central and peripheral control of reproduction, but their possible interaction has been poorly investigated in mammals. This manuscript analyzes their possible reciprocal modulation in the control of the HPG axis. Materials and methods: Adolescent male rats were treated with kisspeptin-10 (Kp10) and endocannabinoid anandamide (AEA), the latter alone or in combination with the type 1 cannabinoid receptor (CB1) antagonist rimonabant (SR141716A). The hypothalamic KS system and GnRH expression, circulating sex steroids and kisspeptin (Kiss1) levels, and intratesticular KS and ECS were evaluated by immunohistochemical and molecular methods. Non-coding RNAs (i.e., miR145-5p, miR-132-3p, let7a-5p, let7b-5p) were also considered. Results: Circulating hormonal values were not significantly affected by Kp10 or AEA; in the hypothalamus, Kp10 significantly increased GnRH mRNA and aromatase Cyp19, Kiss1, and Kiss1 receptor (Kiss1R) proteins. By contrast, AEA treatment affected the hypothalamic KS at the protein levels, with opposite effects on the ligand and receptor, and SR141716A was capable of attenuating the AEA effects. Among the considered non-coding RNA, only the expression of miR145-5p was positively affected by AEA but not by Kp10 treatment. Localization of Kiss1+/Kiss1R+ neurons in the arcuate nucleus revealed an increase of Kiss1R-expressing neurons in Kp10- and AEA-treated animals associated with enlargement of the lateral ventricles in Kp10-treated animals. In the brain and testis, the selected non-coding RNA was differently modulated by Kp10 or AEA. Lastly, in the testis, AEA treatment affected the KS at the protein levels, whereas Kp10 affected the intragonadal levels of CB1 and FAAH, the main modulator of the AEA tone. Changes in pubertal transition-related miRNAs and the intratesticular distribution of Kiss1, Kiss1R, CB1, and CB2 following KP and AEA treatment corroborate the KS-ECS crosstalk also showing that the CB1 receptor is involved in this interplay. Conclusion: For the first time in mammals, we report the modulation of the KS in both the hypothalamus and testis by AEA and revealed the KP-dependent modulation of CB1 and FAAH in the testis. KP involvement in the progression of spermatogenesis is also suggested.
Subject(s)
Kisspeptins , MicroRNAs , Male , Rats , Animals , Kisspeptins/genetics , Kisspeptins/metabolism , Receptors, Kisspeptin-1/genetics , Endocannabinoids/pharmacology , Endocannabinoids/metabolism , Rimonabant/metabolism , Rimonabant/pharmacology , Hypothalamus/metabolism , Gonadotropin-Releasing Hormone/metabolism , Mammals/metabolism , Reproduction , RNA, Untranslated/metabolism , MicroRNAs/metabolismABSTRACT
AIMS: Acute and chronic Δ9-THC exposure paradigms affect the body differently. More must be known about the impact of chronic Δ9-THC on cannabinoid-1 (CB1R) and mu-opioid (MOR) receptor levels in the brain. The present study examined chronic Δ9-THC's effects on CB1R and MOR levels and locomotor activity. MAIN METHODS: Adolescent Sprague-Dawley rats were given daily intraperitoneal injections of Δ9-THC [0.75mg/kg (low dose or LD) or 2.0 mg/kg (high dose or HD)] or vehicle for 24 days, and locomotion in the open field was tested after the first and fourth weeks of chronic Δ9-THC exposure. Brains were harvested at the end of treatment. [3H] SR141716A and [3H] DAMGO autoradiography assessed CB1R and MOR levels, respectively. KEY FINDINGS: Relative to each other, chronic HD rats showed reduced vertical plane (VP) entries and time, while LD rats had increased VP entries and time for locomotion, as assessed by open-field testing; no effects were found relative to the control. Autoradiography analyses showed that HD Δ9-THC significantly decreased CB1R binding relative to LD Δ9-THC in the cingulate (33%), primary motor (42%), secondary motor (33%) somatosensory (38%), rhinal (38%), and auditory (50%) cortices; LD Δ9-THC rats displayed elevated binding in the primary motor (33% increase) and hypothalamic (33% increase) regions compared with controls. No significant differences were observed in MOR binding for the LD or HD compared to the control. SIGNIFICANCE: These results demonstrate that chronic Δ9-THC dose-dependently altered CB1R levels throughout the brain and locomotor activity in the open field.
Subject(s)
Cannabinoids , Dronabinol , Rats , Animals , Dronabinol/pharmacology , Rimonabant/metabolism , Rimonabant/pharmacology , Rats, Sprague-Dawley , Exploratory Behavior , Cannabinoids/pharmacology , Brain/metabolismABSTRACT
Assessing the role of cannabinoid (CB) receptors in behavior is relevant given the trend toward the legalization of medicinal and recreational marijuana. The present research aims at bridging a gap in our understanding of CB-receptor function in animal models of frustrative nonreward. These experiments were designed to (1) determine the effects of chronic administration of the nonselective CB1-receptor agonist WIN 55,212-2 (WIN) on reward downshift in rats and (2) determine whether the effects of chronic WIN were reducible to acute effects. In Experiment 1, chronic WIN (7 daily injections, 10 mg/kg, ip) accelerated the recovery of consummatory behavior after a 32-to-4% sucrose downshift relative to vehicle controls. In addition, chronic WIN eliminated the preference for an unshifted lever when the other lever was subject to a 12-to-2 pellet downshift in free-choice trials, but only in animals with previous experience with a sucrose downshift. In Experiment 2, acute WIN (1 mg/kg, ip) reduced consummatory behavior, but did not affect recovery from a 32-to-4% sucrose downshift. The antagonist SR 141716A (3 mg/kg, ip) also failed to interfere with recovery after the sucrose downshift. In Experiment 3, acute WIN administration (1 mg/kg, ip) did not affect free-choice behavior after a pellet downshift, although it reduced lever pressing and increased magazine entries relative to vehicle controls. The effects of chronic WIN on frustrative nonreward were not reducible to acute effects of the drug. Chronic WIN treatment in rats, like chronic marijuana use in humans, seems to increase resistance to the effects of frustrative nonreward.
Subject(s)
Benzoxazines/pharmacology , Cannabinoid Receptor Agonists/pharmacology , Consummatory Behavior/drug effects , Morpholines/pharmacology , Naphthalenes/pharmacology , Receptors, Cannabinoid/metabolism , Animals , Cannabinoid Receptor Antagonists/pharmacology , Choice Behavior/drug effects , Conditioning, Operant/drug effects , Male , Rats , Rats, Wistar , Reward , Rimonabant/pharmacology , Sucrose/pharmacologyABSTRACT
Despite a growing acceptance that withdrawal symptoms can emerge following discontinuation of cannabis products, especially in high-intake chronic users, there are no Food and Drug Administration (FDA)-approved treatment options. Drug development has been hampered by difficulties studying cannabis withdrawal in laboratory animals. One preclinical approach that has been effective in studying withdrawal from drugs in several pharmacological classes is antagonist drug discrimination. The present studies were designed to examine this paradigm in squirrel monkeys treated daily with the long-acting CB1 agonist AM2389 (0.01 mg/kg) and trained to discriminate the CB1 inverse agonist/antagonist rimonabant (0.3 mg/kg) from saline. The discriminative-stimulus effects of rimonabant were both dose and time dependent and, importantly, could be reproduced by discontinuation of agonist treatment. Antagonist substitution tests with the CB1 neutral antagonists AM4113 (0.03-0.3 mg/kg), AM6527 (0.03-1.0 mg/kg), and AM6545 (0.03-1.0 mg/kg) confirmed that the rimonabant discriminative stimulus also could be reproduced by CB1 antagonists lacking inverse agonist action. Agonist substitution tests with the phytocannabinoid ∆9-tetrahydrocannabinol (0.1-1.0 mg/kg), synthetic CB1 agonists nabilone (0.01-0.1 mg/kg), AM4054 (0.01-0.03 mg/kg), K2/Spice compound JWH-018 (0.03-0.3 mg/kg), FAAH-selective inhibitors AM3506 (0.3-5.6 mg/kg), URB597 (3.0-5.6 mg/kg), and nonselective FAAH/MGL inhibitor AM4302 (3.0-10.0 mg/kg) revealed that only agonists with CB1 affinity were able to reduce the rimonabant-like discriminative stimulus effects of withholding daily agonist treatment. Although the present studies did not document physiologic disturbances associated with withdrawal, the results are consistent with the view that the cannabinoid antagonist drug discrimination paradigm provides a useful screening procedure for examining the ability of candidate medications to attenuate the interoceptive stimuli provoked by cannabis discontinuation. SIGNIFICANCE STATEMENT: Despite a growing acceptance that withdrawal symptoms can emerge following the discontinuation of cannabis products, especially in high-intake chronic users, there are no FDA-approved pharmacotherapies to assist those seeking treatment. The present studies systematically examined cannabinoid antagonist drug discrimination, a preclinical animal model that is designed to appraise the ability of candidate medications to attenuate the interoceptive effects that accompany abrupt cannabis abstinence.
Subject(s)
Cannabinoid Receptor Antagonists/therapeutic use , Discrimination, Psychological , Disease Models, Animal , Substance Withdrawal Syndrome/drug therapy , Animals , Benzopyrans/administration & dosage , Benzopyrans/adverse effects , Benzopyrans/therapeutic use , Cannabinoid Receptor Agonists/administration & dosage , Cannabinoid Receptor Agonists/adverse effects , Cannabinoid Receptor Agonists/therapeutic use , Cannabinoid Receptor Antagonists/administration & dosage , Cannabinoid Receptor Antagonists/adverse effects , Drug Evaluation, Preclinical/methods , Drug Substitution/methods , Male , Rimonabant/administration & dosage , Rimonabant/adverse effects , Rimonabant/therapeutic use , Saimiri , Substance Withdrawal Syndrome/psychologyABSTRACT
Pain is susceptible to various cognitive factors. Suppression of pain by hunger is well known, but the effect of food intake after fasting (i.e. refeeding) on pain remains unknown. In the present study, we examined whether inflammatory pain behavior is affected by 24 h fasting and 2 h refeeding. In formalin-induced acute inflammatory pain model, fasting suppressed pain behavior only in the second phase and the analgesic effect was also observed after refeeding. Furthermore, in Complete Freund's adjuvant-induced chronic inflammatory pain model, both fasting and refeeding reduced spontaneous pain response. Refeeding with non-calorie agar produced an analgesic effect. Besides, intraperitoneal (i.p.) administration of glucose after fasting, which mimics calorie recovery following refeeding, induced analgesic effect. Administration of opioid receptor antagonist (naloxone, i.p.) and cannabinoid receptor antagonist (SR 141716, i.p.) reversed fasting-induced analgesia, but did not affect refeeding-induced analgesia in acute inflammatory pain model. Taken together, our results show that refeeding produce analgesia in inflammatory pain condition, which is associated with eating behavior and calorie recovery effect.
Subject(s)
Acute Pain/diet therapy , Chronic Pain/diet therapy , Eating/psychology , Glucose/administration & dosage , Hyperalgesia/diet therapy , Pain Management/methods , Acute Pain/etiology , Acute Pain/physiopathology , Acute Pain/psychology , Analgesics, Opioid/pharmacology , Animals , Chronic Pain/etiology , Chronic Pain/physiopathology , Chronic Pain/psychology , Disease Models, Animal , Eating/physiology , Food Deprivation/physiology , Formaldehyde/administration & dosage , Freund's Adjuvant/administration & dosage , Hot Temperature/adverse effects , Hyperalgesia/etiology , Hyperalgesia/physiopathology , Hyperalgesia/psychology , Inflammation , Injections, Intraperitoneal , Male , Mice , Mice, Inbred C57BL , Naloxone/pharmacology , Narcotic Antagonists/pharmacology , Pain Measurement , Rimonabant/pharmacologyABSTRACT
In high-fat diet (HFD) induced nonalcoholic fatty liver disease (NAFLD), there is an increase in the endocannabinoid system activity, which significantly contributes to steatosis development. The aim of our study was to investigate the effects of cannabinoid receptor type 1 blockade on adipokine and proinflammatory cytokine content in adipose and hepatic tissue in mice with NAFLD. Male mice C57BL/6 were divided into a control group fed with a control diet for 20 weeks (C, n = 6) a group fed with a HFD for 20 weeks (HF, n = 6), a group fed with a control diet and treated with rimonabant after 18 weeks (R, n = 9), and a group fed with HFD and treated with rimonabant after 18 weeks (HFR, n = 10). Rimonabant significantly decreased leptin, resistin, apelin, visfatin, interleukin 6 (IL-6), and interferon-γ (IFN-γ) concentration in subcutaneous and visceral adipose tissue in the HFR group compared to the HF group (p < 0.01). Rimonabant reduced hepatic IL-6 and IFN-γ concentration as well as plasma glucose and insulin concentration and the homeostatic model assessment index in the HFR group compared to the HF group (p < 0.01). It can be concluded that the potential usefulness of CB1 blockade in the treatment of HFD-induced NAFLD is due to modulation of the adipokine profile and proinflammatory cytokines in both adipose tissues and liver as well as glucose metabolism.
Subject(s)
Cannabinoid Receptor Antagonists/pharmacology , Cytokines/metabolism , Non-alcoholic Fatty Liver Disease/drug therapy , Receptor, Cannabinoid, CB1/antagonists & inhibitors , Rimonabant/pharmacology , Adipokines/metabolism , Adipose Tissue/drug effects , Adipose Tissue/metabolism , Animals , Blood Glucose/drug effects , Cannabinoid Receptor Antagonists/therapeutic use , Diet, High-Fat/adverse effects , Disease Models, Animal , Drug Evaluation, Preclinical , Glucose/metabolism , Humans , Liver/drug effects , Liver/metabolism , Male , Mice , Mice, Inbred C57BL , Non-alcoholic Fatty Liver Disease/blood , Non-alcoholic Fatty Liver Disease/etiology , Non-alcoholic Fatty Liver Disease/pathology , Rimonabant/therapeutic useABSTRACT
Recently, multiple compounds have been synthesized that target the allosteric binding site(s) of CB1. These CB1 positive allosteric modulators may capture the benefits of cannabinoid receptor activation without unwanted psychoactive effects, such as sedation. For example, ZCZ011 blocks neuropathic pain, absent the catalepsy, sedation, and hypothermia caused by CB1 orthosteric modulators, including Δ9-tetrahydrocannabinol (THC). The primary goal of the present study was to evaluate the potential of ZCZ011 to attenuate somatic signs of cannabinoid withdrawal in mice. Mice were repeatedly administered THC (10â¯mg/kg, s.c.) or vehicle, and withdrawal was either precipitated using the CB1 antagonist rimonabant (3â¯mg/kg, i.p.) or elicited spontaneously via THC abstinence. ZCZ011 (≥10â¯mg/kg, i.p.) significantly attenuated somatic signs of withdrawal, including head twitches and paw tremors, but had no effect on locomotor activity or conditioned place preference. We next tested the antiulcerogenic properties of CB1 positive allosteric modulation. Mice were fasted for 22â¯h, administered ZCZ011, and gastric hemorrhages were induced with the nonsteroidal anti-inflammatory drug diclofenac sodium (100â¯mg/kg, p.o.). ZCZ011 alone had no effect on gastric ulceration, but ZCZ011 (≥10â¯mg/kg) blocked ulcer formation when combined with a subthreshold MAGL inhibitor (JZL184; 1â¯mg/kg, i.p.). Thus, CB1 positive allosteric modulation is a novel approach to treat cannabinoid dependence and gastric inflammation.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Benzodioxoles/therapeutic use , Cannabinoid Receptor Agonists/pharmacology , Diclofenac/pharmacology , Dronabinol/pharmacology , Gastritis/chemically induced , Gastritis/drug therapy , Indoles/therapeutic use , Piperidines/therapeutic use , Receptor, Cannabinoid, CB1/metabolism , Substance Withdrawal Syndrome/drug therapy , Thiophenes/therapeutic use , Allosteric Regulation , Allosteric Site , Animals , Anti-Inflammatory Agents, Non-Steroidal/administration & dosage , Benzodioxoles/pharmacology , Cannabinoid Receptor Agonists/administration & dosage , Diclofenac/administration & dosage , Dronabinol/administration & dosage , Drug Therapy, Combination , Indoles/pharmacology , Locomotion/drug effects , Male , Mice , Mice, Inbred C57BL , Mice, Inbred ICR , Monoacylglycerol Lipases/antagonists & inhibitors , Peptic Ulcer Hemorrhage/chemically induced , Peptic Ulcer Hemorrhage/drug therapy , Piperidines/pharmacology , Receptor, Cannabinoid, CB1/antagonists & inhibitors , Rimonabant/pharmacology , Stomach Ulcer/chemically induced , Stomach Ulcer/drug therapy , Thiophenes/pharmacologyABSTRACT
Δ9-tetrahydracannabinol (THC) is recognized as an effective treatment for nausea and vomiting via its action on the cannabinoid 1 (CB1) receptor. Paradoxically, there is evidence that THC can also produce nausea and vomiting. Using the conditioned gaping model of nausea in rats, we evaluated the ability of several doses of THC (0.0, 0.5, 5 and 10â¯mg/kg, i.p.) to produced conditioned gaping reactions. We then investigated the ability of the CB1 receptor antagonist, rimonabant, to block the establishment of THC-induced conditioned gaping. Real-time polymerase chain reaction (RT-PCR) was then used to investigate changes in endocannabinoid related genes in various brain regions in rats chronically treated with vehicle (VEH), 0.5 or 10â¯mg/kg THC. THC produced dose-dependent gaping, with 5 and 10â¯mg/kg producing significantly more gaping reactions than VEH or 0.5â¯mg/kg THC, a dose known to have anti-emetic properties. Pre-treatment with rimonabant reversed this effect, indicating that THC-induced conditioned gaping was CB1 receptor mediated. The RT-PCR analysis revealed an upregulation of genes for the degrading enzyme, monoacylglycerol lipase (MAGL), of the endocannabinoid, 2-arachidolyl glycerol (2-AG), in the hypothalamus of rats treated with 10â¯mg/kg THC. No changes in the expression of relevant genes were found in nausea (interoceptive insular cortex) or vomiting (dorsal vagal complex) related brain regions. These findings support the hypothesis that THC-induced nausea is a result of a dysregulated hypothalamic-pituitary-adrenal axis leading to an overactive stress response.
Subject(s)
Arachidonic Acids/biosynthesis , Dronabinol/administration & dosage , Dronabinol/pharmacology , Endocannabinoids/biosynthesis , Glycerides/biosynthesis , Hypothalamus/drug effects , Hypothalamus/metabolism , Monoacylglycerol Lipases/biosynthesis , Nausea/prevention & control , Animals , Cerebral Cortex/metabolism , Dose-Response Relationship, Drug , Dronabinol/antagonists & inhibitors , Male , Nausea/chemically induced , Rats , Rimonabant/pharmacology , Vagus Nerve/metabolismABSTRACT
Obesity is one of the major public health issues, and its prevalence is steadily increasing all the world over. The endocannabinoid system (ECS) has been shown to be involved in the intake of palatable food via activation of cannabinoid 1 receptor (CB1R). However, the involvement of lingual CB1R in the orosensory perception of dietary fatty acids has never been investigated. In the present study, behavioral tests on CB1R-/- and wild type (WT) mice showed that the invalidation of Cb1r gene was associated with low preference for solutions containing rapeseed oil or a long-chain fatty acid (LCFA), such as linoleic acid (LA). Administration of rimonabant, a CB1R inverse agonist, in mice also brought about a low preference for dietary fat. No difference in CD36 and GPR120 protein expressions were observed in taste bud cells (TBC) from WT and CB1R-/- mice. However, LCFA induced a higher increase in [Ca2+]i in TBC from WT mice than that in TBC from CB1R-/- mice. TBC from CB1R-/- mice also exhibited decreased Proglucagon and Glp-1r mRNA and a low GLP-1 basal level. We report that CB1R is involved in fat taste perception via calcium signaling and GLP-1 secretion.
Subject(s)
Fatty Acids , Food Preferences , Obesity/genetics , Receptor, Cannabinoid, CB1/genetics , Taste Buds/metabolism , Taste Perception/genetics , Taste/genetics , Animals , CD36 Antigens/genetics , CD36 Antigens/metabolism , Calcium Signaling/genetics , Cannabinoid Receptor Antagonists/pharmacology , Dietary Fats , Glucagon-Like Peptide 1/metabolism , Glucagon-Like Peptide-1 Receptor/genetics , Glucagon-Like Peptide-1 Receptor/metabolism , Linoleic Acid , Male , Mice, Knockout , Obesity/etiology , Proglucagon/genetics , Proglucagon/metabolism , RNA, Messenger/metabolism , Rapeseed Oil , Receptor, Cannabinoid, CB1/metabolism , Receptors, G-Protein-Coupled/genetics , Receptors, G-Protein-Coupled/metabolism , Rimonabant/pharmacologyABSTRACT
BACKGROUND AND PURPOSE: Gabapentin is commonly prescribed for nerve pain but may also cause dizziness, sedation and gait disturbances. Similarly, inhibition of the endogenous cannabinoid enzyme monoacylglycerol lipase (MAGL) has antinociceptive and anti-inflammatory properties but also induces sedation in mice at high doses. To limit these side effects, the present study investigated the analgesic effects of coadministering a MAGL inhibitor with gabapentin. EXPERIMENTAL APPROACH: Mice subjected to the chronic constriction injury model of neuropathic pain were administered the MAGL inhibitor KML29 (1-40 mg·kg-1 , i.p.), gabapentin (1-50 mg·kg-1 , i.p.) or both compounds. Mice were tested for mechanical and cold allodynia. The function and expression of cannabinoid CB1 receptors in whole brain homogenates and lipid profile of spinal cords were assessed after repeated drug administration. KEY RESULTS: The combination of low-dose KML29:gabapentin additively attenuated mechanical allodynia and synergistically reduced cold allodynia. The CB1 antagonist, rimonabant, partially reversed the anti-allodynic effects of KML29:gabapentin in mechanical allodynia but not cold allodynia. The anti-allodynic effects of KML29:gabapentin did not undergo tolerance in mechanical allodynia after repeated administration but produced mild tolerance in cold allodynia. High dose KML29 alone reduced CB1 receptor expression and function, but KML29:gabapentin reduced the density of CB1 receptors but did not alter their function. KML29:gabapentin influenced additional signalling pathways (including fatty acids) other than the pathways activated by a higher dose of either drug alone. CONCLUSION AND IMPLICATIONS: These data support the strategy of combining MAGL inhibition with a commonly prescribed analgesic as a therapeutic approach for attenuating neuropathic pain.
Subject(s)
Amines/pharmacology , Analgesics/pharmacology , Benzodioxoles/pharmacology , Cyclohexanecarboxylic Acids/pharmacology , Neuralgia/drug therapy , Piperidines/pharmacology , gamma-Aminobutyric Acid/pharmacology , Amines/administration & dosage , Analgesics/administration & dosage , Animals , Benzodioxoles/administration & dosage , Cyclohexanecarboxylic Acids/administration & dosage , Disease Models, Animal , Dose-Response Relationship, Drug , Drug Synergism , Drug Tolerance , Enzyme Inhibitors/administration & dosage , Enzyme Inhibitors/pharmacology , Gabapentin , Hyperalgesia/drug therapy , Male , Mice , Mice, Inbred C57BL , Monoacylglycerol Lipases/antagonists & inhibitors , Piperidines/administration & dosage , Pyrazoles/pharmacology , Receptor, Cannabinoid, CB1/drug effects , Rimonabant , Signal Transduction/drug effects , gamma-Aminobutyric Acid/administration & dosageABSTRACT
Treatment of TBI remains a major unmet medical need, with 2.5 million new cases of traumatic brain injury (TBI) each year in Europe and 1.5 million in the USA. This single-center proof-of-concept preclinical study tested the hypothesis that pharmacologic neurostimulation with proconvulsants, either atipamezole, a selective α2-adrenoceptor antagonist, or the cannabinoid receptor 1 antagonist SR141716A, as monotherapy would improve functional recovery after TBI. A total of 404 adult Sprague-Dawley male rats were randomized into two groups: sham-injured or lateral fluid-percussion-induced TBI. The rats were treated with atipamezole (started at 30min or 7 d after TBI) or SR141716A (2min or 30min post-TBI) for up to 9 wk. Total follow-up time was 14 wk after treatment initiation. Outcome measures included motor (composite neuroscore, beam-walking) and cognitive performance (Morris water-maze), seizure susceptibility, spontaneous seizures, and cortical and hippocampal pathology. All injured rats exhibited similar impairment in the neuroscore and beam-walking tests at 2 d post-TBI. Atipamezole treatment initiated at either 30min or 7 d post-TBI and continued for 9 wk via subcutaneous osmotic minipumps improved performance in both the neuroscore and beam-walking tests, but not in the Morris water-maze spatial learning and memory test. Atipamezole treatment initiated at 7 d post-TBI also reduced seizure susceptibility in the pentylenetetrazol test 14 wk after treatment initiation, although it did not prevent the development of epilepsy. SR141716A administered as a single dose at 2min post-TBI or initiated at 30min post-TBI and continued for 9 wk had no recovery-enhancing or antiepileptogenic effects. Mechanistic studies to assess the α2-adrenoceptor subtype specificity of the disease-modifying effects of atipametzole revealed that genetic ablation of α2A-noradrenergic receptor function in Adra2A mice carrying an N79P point mutation had antiepileptogenic effects after TBI. On the other hand, blockade of α2C-adrenoceptors using the receptor subtype-specific antagonist ORM-12741 had no favorable effects on the post-TBI outcome. Finally, to assess whether regulation of the post-injury inflammatory response by atipametzole in glial cells contributed to a favorable outcome, we investigated the effect of atipamezole on spontaneous and/or lipopolysaccharide-stimulated astroglial or microglial cytokine release in vitro. We observed no effect. Our data demonstrate that a 9-wk administration of α2A-noradrenergic antagonist, atipamezole, is recovery-enhancing after TBI.
Subject(s)
Anticonvulsants/pharmacology , Epilepsy, Post-Traumatic/drug therapy , Imidazoles/pharmacology , Adrenergic alpha-2 Receptor Antagonists/pharmacology , Animals , Axons/drug effects , Axons/physiology , Body Temperature/drug effects , Brain/drug effects , Brain/physiopathology , Drug Evaluation, Preclinical , Epilepsy, Post-Traumatic/physiopathology , Epilepsy, Post-Traumatic/psychology , Male , Motor Activity/drug effects , Neuronal Plasticity/drug effects , Neuronal Plasticity/physiology , Neuroprotective Agents/pharmacology , Piperidines/pharmacology , Proof of Concept Study , Pyrazoles/pharmacology , Random Allocation , Rats, Sprague-Dawley , Recovery of Function/drug effects , Rimonabant , Seizures/drug therapy , Seizures/physiopathology , Spatial Memory/drug effectsABSTRACT
Monoacylglycerol lipase (MAGL) is a serine hydrolase that acts as a principal degradative enzyme for the endocannabinoid 2-arachidonoylglycerol (2-AG). In addition to terminating the signaling function of 2-AG, MAGL liberates arachidonic acid to be used as a primary source for neuroinflammatory prostaglandin synthesis in the brain. MAGL activity also contributes to cancer pathogenicity by producing precursors for tumor-promoting bioactive lipids. Pharmacological inhibitors of MAGL provide valuable tools for characterization of MAGL and 2-AG signaling pathways. They also hold great therapeutic potential to treat several pathophysiological conditions, such as pain, neurodegenerative disorders, and cancer. We have previously reported piperidine triazole urea, {4-[bis-(benzo[d][1,3]dioxol-5-yl)methyl]-piperidin-1-yl}(1H-1,2,4-triazol-1-yl)methanone (JJKK-048), to be an ultrapotent and highly selective inhibitor of MAGL in vitro. Here, we characterize in vivo effects of JJKK-048. Acute in vivo administration of JJKK-048 induced a massive increase in mouse brain 2-AG levels without affecting brain anandamide levels. JJKK-048 appeared to be extremely potent in vivo. Activity-based protein profiling revealed that JJKK-048 maintains good selectivity toward MAGL over other serine hydrolases. Our results are also the first to show that JJKK-048 promoted significant analgesia in a writhing test with a low dose that did not cause cannabimimetic side effects. At a high dose, JJKK-048 induced analgesia both in the writhing test and in the tail-immersion test, as well as hypomotility and hyperthermia, but not catalepsy.
Subject(s)
Benzodioxoles/pharmacology , Enzyme Inhibitors/pharmacology , Monoacylglycerol Lipases/antagonists & inhibitors , Piperidines/pharmacology , Animals , Arachidonic Acids/metabolism , Behavior, Animal/drug effects , Benzodioxoles/adverse effects , Benzodioxoles/pharmacokinetics , Brain/drug effects , Brain/metabolism , Dose-Response Relationship, Drug , Endocannabinoids/metabolism , Enzyme Inhibitors/adverse effects , Enzyme Inhibitors/pharmacokinetics , Glycerides/metabolism , Hypothermia/chemically induced , Male , Mice , Nociception/drug effects , Piperidines/adverse effects , Piperidines/pharmacokinetics , Pyrazoles/pharmacology , RimonabantABSTRACT
Weight loss, regular exercise, and diet composition modification seem to improve biochemical and histologic abnormalities. Other therapies directed at insulin resistance, oxidative stress, cytoprotection, and fibrosis may also offer benefits. Insulin sensitizers and vitamin E seem to be the most promising; however, they cause side effects. A multifaceted approach of lifestyle modifications, weight loss, and pharmacotherapy can be used in combination, but no single treatment approach has proved universally applicable to the general population with nonalcoholic steatohepatitis (NASH). Continuous clinical and preclinical studies on existing and potential drugs are needed to improve treatment of nonalcoholic fatty liver disease/NASH.
Subject(s)
Antioxidants/therapeutic use , Fatty Acids, Omega-3/therapeutic use , Hypoglycemic Agents/therapeutic use , Non-alcoholic Fatty Liver Disease/drug therapy , Angiotensin Receptor Antagonists/therapeutic use , Anti-Inflammatory Agents, Non-Steroidal/therapeutic use , Anti-Obesity Agents/therapeutic use , Anticholesteremic Agents/therapeutic use , Cannabinoid Receptor Antagonists/therapeutic use , Cholagogues and Choleretics/therapeutic use , Glucagon-Like Peptide-1 Receptor/agonists , Humans , Insulin Resistance , Lactones/therapeutic use , Metformin/therapeutic use , Non-alcoholic Fatty Liver Disease/therapy , Orlistat , Pentoxifylline/therapeutic use , Piperidines/therapeutic use , Probiotics/therapeutic use , Pyrazoles/therapeutic use , Rimonabant , Synbiotics , Thiazolidinediones/therapeutic use , Ursodeoxycholic Acid/therapeutic use , Vitamin E/therapeutic useABSTRACT
Sativex(®), an equimolecular combination of Δ(9)-tetrahydrocannabinol-botanical drug substance (Δ(9)-THC-BDS) and cannabidiol-botanical drug substance (CBD-BDS), is a licensed medicine that may be prescribed for alleviating specific symptoms of multiple sclerosis (MS) such as spasticity and pain. However, further evidence suggest that it could be also active as disease-modifying therapy given the immunomodulatory, anti-inflammatory and cytoprotective properties of their two major components. In this study, we investigated this potential in the experimental autoimmune encephalitis (EAE) model of MS in mice. We compared the effect of a Sativex-like combination of Δ(9)-THC-BDS (10 mg/kg) and CBD-BDS (10 mg/kg) with Δ(9)-THC-BDS (20 mg/kg) or CBD-BDS (20 mg/kg) administered separately by intraperitoneal administration to EAE mice. Treatments were initiated at the time that symptoms appear and continued up to the first relapse of the disease. The results show that the treatment with a Sativex-like combination significantly improved the neurological deficits typical of EAE mice, in parallel with a reduction in the number and extent of cell aggregates present in the spinal cord which derived from cell infiltration to the CNS. These effects were completely reproduced by the treatment with Δ(9)-THC-BDS alone, but not by CBD-BDS alone which only delayed the onset of the disease without improving disease progression and reducing the cell infiltrates in the spinal cord. Next, we investigated the potential targets involved in the effects of Δ(9)-THC-BDS by selectively blocking CB(1) or PPAR-γ receptors, and we found a complete reversion of neurological benefits and the reduction in cell aggregates only with rimonabant, a selective CB(1) receptor antagonist. Collectively, our data support the therapeutic potential of Sativex as a phytocannabinoid formulation capable of attenuating EAE progression, and that the active compound was Δ(9)-THC-BDS acting through CB(1) receptors.
Subject(s)
Cannabinoid Receptor Modulators/pharmacology , Dronabinol/pharmacology , Encephalomyelitis, Autoimmune, Experimental/drug therapy , Neuroprotective Agents/pharmacology , Plant Extracts/pharmacology , Receptor, Cannabinoid, CB1/metabolism , Animals , Cannabidiol , Drug Combinations , Drug Evaluation, Preclinical , Encephalomyelitis, Autoimmune, Experimental/metabolism , Encephalomyelitis, Autoimmune, Experimental/pathology , Female , Mice, Inbred C57BL , Photomicrography , Piperidines/pharmacology , Pyrazoles/pharmacology , Receptor, Cannabinoid, CB1/antagonists & inhibitors , Rimonabant , Spinal Cord/drug effects , Spinal Cord/metabolism , Spinal Cord/pathologyABSTRACT
AIM: To investigate the in vivo metabolic effects of treatment with BPR0912, a novel and potent peripheral cannabinoid receptor 1 (CB1R) antagonist, on both normal mice and diet-induced obese (DIO) mice. METHODS: The acute peripheral effects of BPR0912 administration on gastrointestinal transit and energy metabolism in normal mice were investigated. The effects of chronic BPR0912 treatment were compared with those of rimonabant using DIO mice. Alterations to body weight and biochemical and metabolic variables were determined. RESULTS: Acute treatment with BPR0912 did not alter food intake or energy metabolism, but efficiently reversed CB1R-mediated gastrointestinal delay. Chronic treatment of DIO mice with BPR0912 showed that BPR0912 exerts a food intake-independent mechanism, which contributes to weight loss. Genes involved in ß-oxidation and thermogenesis were upregulated in white adipose tissue (WAT) in addition to increased lipolytic activity, whereas Ucp1 expression was induced in brown adipose tissue (BAT) and body temperature was elevated. Expression of the ß2-adrenoceptor was specifically elevated in both WAT and BAT in a manner dependent on the BPR0912 dose. Lastly, chronic BPR0912 treatment was more efficacious than rimonabant in reducing hepatic triglycerides in DIO mice. CONCLUSION: BPR0912 exhibits significant in vivo efficacy in inducing food intake-independent weight loss in DIO mice, while tending to reduce their hepatic steatosis. The thermogenic effects of BPR0912, as well as its modulation of protein and gene expression patterns in WAT and BAT, may enhance its efficacy as an anti-obesity agent. The results of the present study support the benefits of the use of peripheral CB1R antagonists to combat metabolic disorders.
Subject(s)
Anti-Obesity Agents/pharmacology , Cannabinoid Receptor Antagonists/pharmacology , Obesity/drug therapy , Pyrazoles/pharmacology , Receptor, Cannabinoid, CB1/antagonists & inhibitors , Thermogenesis/drug effects , Thiophenes/pharmacology , Weight Loss/drug effects , Adipose Tissue, Brown/drug effects , Adipose Tissue, Brown/metabolism , Adipose Tissue, White/drug effects , Adipose Tissue, White/metabolism , Animals , Dose-Response Relationship, Drug , Drug Evaluation, Preclinical , Eating/drug effects , Energy Metabolism/drug effects , Fatty Liver/drug therapy , Fatty Liver/etiology , Ion Channels/genetics , Lipolysis/drug effects , Male , Mice , Mice, Inbred C57BL , Mitochondrial Proteins/genetics , Obesity/complications , Piperidines/pharmacology , Rimonabant , Uncoupling Protein 1ABSTRACT
BACKGROUND: The endocannabinoids system (ECs) mediated mainly by CB1 and CB2 receptors plays an important role in non-alcoholic fatty liver disease by regulating lipid metabolism. This study is to further investigate the expression of CB1 and CB2 in the fat accumulation liver cells and to identify possible underlying mechanism by detecting the key lipogenesis factors. METHODS: Sodium oleate and sodium palmitate were added into the HepG2 cell line for forming fat accumulation liver cell. MTT assay was used to test the cell's cytotoxicity. The accumulation rate of fat in HepG2 cell was analyzed by the fluorescent staining. The mRNA and protein expression levels of CB1, CB2, SREBP-1c, ChREBP, L-PK, ACC1, FAS, LXRs and RXR were detected by RT-PCR and Western blot before and after the use of the antagonist. RESULTS: The receptors of CB1 were expressed in HepG2 cells with low levels while in HepG2 fatty liver cells with higher levels (p < 0.05). However, after the application of antagonist, the expressions were significantly decreased (p < 0.05). The expressions of SREBP-1c, ChREBP and LXRs were detectable in HepG2 cells and the expressions were increased in HepG2 fatty liver cells (p < 0.05). After using the antagonists, the expressions of SREBP-1c, ChREBP, LXRs, ACC1 and FAS were significantly decreased (p < 0.05). But L-PK and RXR changed little in two groups (p > 0.05). CONCLUSION: Results of the present study demonstrated that CB1 receptors had important pathophysiological effects on the formation of fatty liver. CB1 receptors could be regulated by SREBP-1c, ChREBP and LXRs. Therefore, targeting CB1 receptors for the treatment of NAFLD might have a potential application value.
Subject(s)
Cannabinoid Receptor Antagonists/pharmacology , Lipogenesis/drug effects , Non-alcoholic Fatty Liver Disease/drug therapy , Piperidines/pharmacology , Pyrazoles/pharmacology , Receptor, Cannabinoid, CB1/antagonists & inhibitors , Drug Evaluation, Preclinical , Hep G2 Cells , Humans , Receptor, Cannabinoid, CB1/metabolism , Receptor, Cannabinoid, CB2/metabolism , RimonabantABSTRACT
BACKGROUND AND PURPOSE: Palmitoylethanolamide (PEA), a naturally occurring acylethanolamide chemically related to the endocannabinoid anandamide, interacts with targets that have been identified in peripheral nerves controlling gastrointestinal motility, such as cannabinoid CB1 and CB2 receptors, TRPV1 channels and PPARα. Here, we investigated the effect of PEA in a mouse model of functional accelerated transit which persists after the resolution of colonic inflammation (post-inflammatory irritable bowel syndrome). EXPERIMENTAL APPROACH: Intestinal inflammation was induced by intracolonic administration of oil of mustard (OM). Mice were tested for motility and biochemical and molecular biology changes 4 weeks later. PEA, oleoylethanolamide and endocannabinoid levels were measured by liquid chromatography-mass spectrometry and receptor and enzyme mRNA expression by qRT-PCR. KEY RESULTS: OM induced transient colitis and a functional post-inflammatory increase in upper gastrointestinal transit, associated with increased intestinal anandamide (but not 2-arachidonoylglycerol, PEA or oleoylethanolamide) levels and down-regulation of mRNA for TRPV1 channels. Exogenous PEA inhibited the OM-induced increase in transit and tended to increase anandamide levels. Palmitic acid had a weaker effect on transit. Inhibition of transit by PEA was blocked by rimonabant (CB1 receptor antagonist), further increased by 5'-iodoresiniferatoxin (TRPV1 antagonist) and not significantly modified by the PPARα antagonist GW6471. CONCLUSIONS AND IMPLICATIONS: Intestinal endocannabinoids and TRPV1 channel were dysregulated in a functional model of accelerated transit exhibiting aspects of post-inflammatory irritable bowel syndrome. PEA counteracted the accelerated transit, the effect being mediated by CB1 receptors (possibly via increased anandamide levels) and modulated by TRPV1 channels.
Subject(s)
Colitis/drug therapy , Disease Models, Animal , Ethanolamines/pharmacology , Gastrointestinal Motility/drug effects , Irritable Bowel Syndrome/drug therapy , Palmitic Acids/pharmacology , Receptor, Cannabinoid, CB1/antagonists & inhibitors , TRPV Cation Channels/antagonists & inhibitors , Amides , Animals , Colitis/chemically induced , Colitis/metabolism , Ethanolamines/administration & dosage , Ethanolamines/antagonists & inhibitors , Inflammation/chemically induced , Inflammation/drug therapy , Inflammation/metabolism , Injections, Intraperitoneal , Irritable Bowel Syndrome/chemically induced , Irritable Bowel Syndrome/metabolism , Male , Mice , Mice, Inbred ICR , Mustard Plant , Palmitic Acids/administration & dosage , Palmitic Acids/antagonists & inhibitors , Piperidines/pharmacology , Plant Oils/administration & dosage , Pyrazoles/pharmacology , RNA, Messenger/genetics , RNA, Messenger/metabolism , Receptor, Cannabinoid, CB1/metabolism , Rimonabant , TRPV Cation Channels/genetics , TRPV Cation Channels/metabolismABSTRACT
Studies have suggested that the endocannabinoid system is implicated in the pathophysiology of schizophrenia. We have recently reported that Spontaneously Hypertensive Rats (SHRs) present a deficit in social interaction that is ameliorated by atypical antipsychotics. In addition, SHRs display hyperlocomotion - reverted by atypical and typical antipsychotics. These results suggest that this strain could be useful to study negative symptoms (modeled by a decrease in social interaction) and positive symptoms (modeled by hyperlocomotion) of schizophrenia and the effects of potential drugs with an antipsychotic profile. The aim of this study was to investigate the effects of WIN55-212,2 (CB1/CB2 agonist), ACEA (CB1 agonist), rimonabant (CB1 inverse agonist), AM404 (anandamide uptake/metabolism inhibitor), capsaicin (agonist TRPV1) and capsazepine (antagonist TRPV1) on the social interaction and locomotion of control animals (Wistar rats) and SHRs. The treatment with rimonabant was not able to alter either the social interaction or the locomotion presented by Wistar rats (WR) and SHR at any dose tested. The treatment with WIN55-212,2 decreased locomotion (1mg/kg) and social interaction (0.1 and 0.3mg/kg) of WR, while the dose of 1mg/kg increased social interaction of SHR. The treatment with ACEA increased (0.3mg/kg) and decreased (1mg/kg) locomotion of both strain. The administration of AM404 increased social interaction and decreased locomotion of SHR (5mg/kg), and decreased social interaction and increased locomotion in WR (1mg/kg). The treatment with capsaicin (2.5mg/kg) increased social interaction of both strain and decreased locomotion of SHR (2.5mg/kg) and WR (0.5mg/kg and 2.5mg/kg). In addition, capsazepine (5mg/kg) decreased locomotion of both strains and increased (5mg/kg) and decreased (10mg/kg) social interaction of WR. Our results indicate that the schizophrenia-like behaviors displayed by SHR are differently altered by cannabinoid and vanilloid drugs when compared to control animals and suggest the endocannabinoid and the vanilloid systems as a potential target for the treatment of schizophrenia.
Subject(s)
Cannabinoid Receptor Modulators/therapeutic use , Interpersonal Relations , Motor Activity/drug effects , Schizophrenia/drug therapy , Schizophrenic Psychology , TRPV Cation Channels/metabolism , Analysis of Variance , Animals , Arachidonic Acids/administration & dosage , Benzoxazines/administration & dosage , Capsaicin/analogs & derivatives , Capsaicin/therapeutic use , Disease Models, Animal , Dose-Response Relationship, Drug , Male , Morpholines/administration & dosage , Naphthalenes/administration & dosage , Piperidines/therapeutic use , Pyrazoles/therapeutic use , Rats , Rats, Inbred SHR , Rats, Wistar , Rimonabant , Schizophrenia/physiopathology , TRPV Cation Channels/agonists , TRPV Cation Channels/antagonists & inhibitorsABSTRACT
Recently, synthetic cannabinoids have been sprayed onto plant material, which is subsequently packaged and sold as "Spice" or "K2" to mimic the effects of marijuana. A recent report identified several synthetic additives in samples of "Spice/K2", including JWH-081, a synthetic ligand for the cannabinoid receptor 1 (CB1). The deleterious effects of JWH-081 on brain function are not known, particularly on CB1 signaling, synaptic plasticity, learning and memory. Here, we evaluated the effects of JWH-081 on pCaMKIV, pCREB, and pERK1/2 signaling events followed by long-term potentiation (LTP), hippocampal-dependent learning and memory tasks using CB1 receptor wild-type (WT) and knockout (KO) mice. Acute administration of JWH-081 impaired CaMKIV phosphorylation in a dose-dependent manner, whereas inhibition of CREB phosphorylation in CB1 receptor WT mice was observed only at higher dose of JWH-081 (1.25 mg/kg). JWH-081 at higher dose impaired CaMKIV and CREB phosphorylation in a time-dependent manner in CB1 receptor WT mice but not in KO mice and failed to alter ERK1/2 phosphorylation. In addition, SR treated or CB1 receptor KO mice have a lower pCaMKIV/CaMKIV ratio and higher pCREB/CREB ratio compared with vehicle or WT littermates. In hippocampal slices, JWH-081 impaired LTP in CB1 receptor WT but not in KO littermates. Furthermore, JWH-081 at higher dose impaired object recognition, spontaneous alternation and spatial memory on the Y-maze in CB1 receptor WT mice but not in KO mice. Collectively our findings suggest that deleterious effects of JWH-081 on hippocampal function involves CB1 receptor mediated impairments in CaMKIV and CREB phosphorylation, LTP, learning and memory in mice.
Subject(s)
Cannabinoids/chemistry , Hippocampus/drug effects , Learning Disabilities/drug therapy , Long-Term Potentiation/drug effects , Memory Disorders/drug therapy , Receptor, Cannabinoid, CB1/metabolism , Animals , CREB-Binding Protein/metabolism , Calcium-Calmodulin-Dependent Protein Kinase Type 4/metabolism , Cannabinoid Receptor Antagonists/pharmacology , Cannabinoids/pharmacology , Disease Models, Animal , Dose-Response Relationship, Drug , Hippocampus/pathology , Indoles/pharmacology , Indoles/toxicity , Learning Disabilities/chemically induced , Learning Disabilities/complications , Learning Disabilities/genetics , Maze Learning/drug effects , Memory Disorders/chemically induced , Memory Disorders/genetics , Memory Disorders/pathology , Mice , Mice, Inbred C57BL , Mice, Knockout , Naphthalenes/pharmacology , Naphthalenes/toxicity , Phosphorylation/drug effects , Phosphorylation/genetics , Piperidines/pharmacology , Pyrazoles/pharmacology , Receptor, Cannabinoid, CB1/deficiency , Rimonabant , Signal Transduction/drug effects , Space Perception/drug effects , Synapses/drug effectsABSTRACT
Obesity is a chronic disease, and it requires chronic therapy. Hypertension, dyslipidemia, diabetes and cardiovascular diseases are leading causes of mortality in the modern world. All of them are strongly linked to obesity. While treating obesity, those conditions are also managed. Obese patients should always be treated through lifestyle interventions, though the results of such interventions are modest. Pharmacotherapy is a second step in the treatment of obesity, approved only when weight loss targets were not reached through lifestyle intervention. During the history of antiobesity drugs, many of them were withdrawn because of their side effects. Various guidelines recommend prescribing drug therapy for obesity through consideration of the potential benefits and limitations. Orlistat deactivates intestinal lipase and inhibits intestinal fat lipolysis. It is actually the only drug on the European market approved for the treatment of obesity. Orlistat therapy reduces weight to a modest extent, but it reduces the incidence of diabetes beyond the result achieved with lifestyle changes. Recently, some effective antiobesity drugs like sibutramine and rimonabant have been removed from the market due to their side effects. The new combination of topimarate and fentermine is approved in the US but not in Europe. The cost effectiveness of long-term pharmacotherapy of obesity is still an unresolved question.