Raphael Mechoulam

Isadora Lopes Cortez, Nicole R Silva, Naielly S Rodrigues, João Francisco C Pedrazzi, Elaine A Del Bel, Raphael Mechoulam, Felipe V Gomes, and Francisco S Guimarães. 2022. “HU-910, a CB2 receptor agonist, reverses behavioral changes in pharmacological rodent models for schizophrenia.” Progress in neuro-psychopharmacology & biological psychiatry, 117, Pp. 110553. Abstract
Despite attenuating the positive symptoms, drugs currently used to treat schizophrenia frequently do not improve the negative symptoms and cognitive impairments. In addition, they show low tolerability, which has been associated with high rates of treatment discontinuation. Recent evidence suggests that the endocannabinoid system may be a target for schizophrenia treatment. The CB2 receptor modulates dopaminergic neurotransmission, which is abnormally enhanced in schizophrenia patients. Here, we aimed to evaluate whether HU-910, a selective CB2 receptor agonist, would reverse schizophrenia-related behavioral changes observed after the acute injections of amphetamine or the N-methyl-d-aspartate receptor (NMDAR) antagonist MK-801. We also investigated the effects of HU-910 in the memory impairment caused by repeated MK-801 administration. Finally, we tested whether HU-910 would produce the cannabinoid tetrad (catalepsy, hypolocomotion, hypothermia, and antinociception). In male C57BL/6 mice, the acute treatment with HU-910 (30 mg/kg) prevented the hyperlocomotion induced by acute MK-801. This effect was blocked by the CB2 receptor antagonist AM630 (1 mg/kg). On the contrary, HU-910 did not prevent the increased locomotor activity caused by acute amphetamine. The acute treatment with HU-910 (3, 10, and 30 mg/kg) also attenuated the impairments in the prepulse inhibition test induced by acute MK-801 and amphetamine. The repeated treatment with HU-910 attenuated the cognitive impairment caused by chronic administration of MK-801 in the novel object recognition test. Furthermore, HU-910 did not produce the cannabinoid tetrad. These results indicate that HU-910 produced antipsychotic-like effects and support further research on the potential therapeutic properties of this compound to treat schizophrenia.
José Diogo S Souza, Antonio W Zuardi, Francisco S Guimarães, Flávia Lima de Osório, Sonia Regina Loureiro, Alline Cristina Campos, Jaime EC Hallak, Rafael G Dos Santos, Isabella Lara Machado Silveira, Karina Pereira-Lima, Julia Cozar Pacheco, Juliana Mayumi Ushirohira, Rafael Rinaldi Ferreira, Karla Cristinne Mancini Costa, Davi Silveira Scomparin, Franciele Franco Scarante, Isabela Pires-Dos-Santos, Raphael Mechoulam, Flávio Kapczinski, Benedito AL Fonseca, Danillo LA Esposito, Maristela Haddad Andraus, and José Alexandre S Crippa. 2022. “Maintained anxiolytic effects of cannabidiol after treatment discontinuation in healthcare workers during the COVID-19 pandemic.” Frontiers in pharmacology, 13, Pp. 856846. Abstract
Objective: To assess whether the effects of oral administration of 300 mg of Cannabidiol (CBD) for 28 days on mental health are maintained for a period after the medication discontinuation. Methods: This is a 3-month follow-up observational and clinical trial study. The data were obtained from two studies performed simultaneously by the same team in the same period and region with Brazilian frontline healthcare workers during the COVID-19 pandemic. Scales to assess emotional symptoms were applied weekly, in the first month, and at weeks eight and 12. Results: The primary outcome was that, compared to the control group, a significant reduction in General Anxiety Disorder-7 Questionnaire (GAD-7) from baseline values was observed in the CBD group on weeks two, four, and eight (Within-Subjects Contrasts, time-group interactions: F(1-125) = 7.67; p = 0.006; $η$(p) (2) = 0.06; F(1-125) = 6.58; p = 0.01; $η$(p) (2) = 0.05; F(1-125) = 4.28; p = 0.04; $η$(p) (2) = 0.03, respectively) after the end of the treatment. Conclusions: The anxiolytic effects of CBD in frontline health care professionals during the COVID-19 pandemic were maintained up to 1 month after the treatment discontinuation, suggesting a persistent decrease in anxiety in this group in the real world. Future double-blind placebo-controlled clinical trials are needed to confirm the present findings and weigh the benefits of CBD therapy against potential undesired or adverse effects.
Nicole Rodrigues Silva, Francisco Isaac Fernandes Gomes, Alexandre Hashimoto Pereira Lopes, Isadora Lopes Cortez, Jéssica Cristina dos Santos, Conceição Elidianne Aníbal Silva, Raphael Mechoulam, Felipe Villela Gomes, Thiago Mattar Cunha, and Francisco Silveira Guimarães. 2022. “The Cannabidiol Analog PECS-101 Prevents Chemotherapy-Induced Neuropathic Pain via PPAR$\gamma$ Receptors.” Neurotherapeutics : the journal of the American Society for Experimental NeuroTherapeutics, 19, 1, Pp. 434–449. Abstract
Chemotherapy-induced peripheral neuropathy (CIPN) is the main dose-limiting adverse effect of chemotherapy drugs such as paclitaxel (PTX). PTX causes marked molecular and cellular damage, mainly in the peripheral nervous system, including sensory neurons in the dorsal root ganglia (DRG). Several studies have shown the therapeutic potential of cannabinoids, including cannabidiol (CBD), the major non-psychotomimetic compound found in the Cannabis plant, to treat peripheral neuropathies. Here, we investigated the efficacy of PECS-101 (former HUF-101), a CBD fluorinated analog, on PTX-induced neuropathic pain in mice. PECS-101, administered after the end of treatment with PTX, did not reverse mechanical allodynia. However, PECS-101 (1 mg/kg) administered along with PTX treatment caused a long-lasting relief of the mechanical and cold allodynia. These effects were blocked by a PPAR$\gamma$, but not CB1 and CB2 receptor antagonists. Notably, the effects of PECS-101 on the relief of PTX-induced mechanical and cold allodynia were not found in macrophage-specific PPAR$\gamma$-deficient mice. PECS-101 also decreased PTX-induced increase in Tnf, Il6, and Aif1 (Iba-1) gene expression in the DRGs and the loss of intra-epidermal nerve fibers. PECS-101 did not alter motor coordination, produce tolerance, or show abuse potential. In addition, PECS-101 did not interfere with the chemotherapeutic effects of PTX. Thus, PECS-101, a new fluorinated CBD analog, could represent a novel therapeutic alternative to prevent mechanical and cold allodynia induced by PTX potentially through the activation of PPAR$\gamma$ in macrophages.
Hana Golan, Raphael Mechoulam, Reem Smoum, Efrat Cohen-Zada, Sara Pri-Chen, Sapir Wiener, Igor Grinberg, Dekel D Bar-Lev, Christeeneh G Haj, Tamar Fisher, and Amos Toren. 2022. “Anti-Tumorigenic Effect of a Novel Derivative of 2-Hydroxyoleic Acid and the Endocannabinoid Anandamide on Neuroblastoma Cells.” Biomedicines, 10, 7. Abstract
Modulation of the endogenous cannabinoid system has been suggested as a potential anticancer strategy. In the search for novel and less toxic therapeutic options, structural modifications of the endocannabinoid anandamide and the synthetic derivative of oleic acid, Minerval (HU-600), were done to obtain 2-hydroxy oleic acid ethanolamide (HU-585), which is an HU-600 derivative with the anandamide side chain. We showed that treatment of SK-N-SH neuroblastoma cells with HU-585 induced a better anti-tumorigenic effect in comparison to HU-600 as evidenced by 3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide assay, colony-forming assay, and migration assay. Moreover, HU-585 demonstrated pro-apoptotic properties shown by increased levels of activated caspase-3 following treatment and a better senescence induction effect in comparison to HU-600, as demonstrated by increased activity of lysosomal $\beta$-galactosidase. Finally, we observed that combined treatment of HU-585 with the senolytic drugs ABT-263 in vitro, and ABT-737 in vivo resulted in enhanced anti-proliferative effects and reduced neuroblastoma xenograft growth in comparison to treatment with HU-585 alone. Based on these results, we suggest that HU-585 is a pro-apoptotic and senescence-inducing compound, better than HU-600. Hence, it may be a beneficial option for the treatment of resistant neuroblastoma especially when combined with senolytic drugs that enhance its anti-tumorigenic effects.
José Alexandre S Crippa, Julia Cozar Pacheco, Antonio W Zuardi, Francisco S Guimarães, Alline Cristina Campos, Flávia Lima de Osório, Sonia Regina Loureiro, Rafael G Dos Santos, José Diogo S Souza, Juliana Mayumi Ushirohira, Rafael Rinaldi Ferreira, Karla Cristinne Mancini Costa, Davi Silveira Scomparin, Franciele Franco Scarante, Isabela Pires-Dos-Santos, Raphael Mechoulam, Flávio Kapczinski, Benedito AL Fonseca, Danillo LA Esposito, Afonso Dinis Costa Passos, Amaury Lelis Dal Fabbro, Fernando Bellissimo-Rodrigues, Eurico Arruda, Sandro Scarpelini, Maristela Haddad Andraus, Julio Cesar Nather Junior, Danilo Tadao Wada, Marcel Koenigkam-Santos, Antonio Carlos Santos, Geraldo Busatto Filho, and Jaime EC Hallak. 2022. “Cannabidiol for COVID-19 Patients with Mild to Moderate Symptoms (CANDIDATE Study): A Randomized, Double-Blind, Placebo-Controlled Clinical Trial.” Cannabis and cannabinoid research, 7, 5, Pp. 658–669. Abstract
{Importance: Owing to its anti-inflammatory properties and antiviral "in vitro" effect against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), cannabidiol (CBD) has been proposed as a potential treatment for coronavirus disease 2019 (COVID-19). Objective: To investigate the safety and efficacy of CBD for treating patients with mild to moderate COVID-19. Design: Randomized, parallel-group, double-blind, placebo-controlled clinical trial conducted between July 7 and October 16, 2020, in two sites in Brazil. Setting: Patients were recruited in an emergency room. Participants: Block randomized patients (1:1 allocation ratio-by a researcher not directly involved in data collection) with mild and moderate COVID-19 living in Ribeirão Preto, Brazil, seeking medical consultation, and those who voluntarily agreed to participate in the study. Interventions: Patients received 300 mg of CBD or placebo added to standard symptomatic care during 14 days. Main Outcome and Measure: The primary outcome was reduction or prevention of the deterioration in clinical status from mild/moderate to severe/critical measured with the COVID-19 Scale or the natural course of the resolution of typical clinical symptoms. Primary study outcome was assessed on days 14, 21, and 28 after enrollment. Results: A total of 321 patients were recruited and assessed for eligibility, and 105 were randomly allocated either in CBD (n=49) or in placebo (n=42) group. Ninety-one participants were included in the analysis of efficacy. There were no baseline between-group differences regarding disease severity ($\chi$(2)=0.025
Samah Shahen-Zoabi, Reem Smoum, Tehila Beiser, Alina Nemirovski, Raphael Mechoulam, and Rami Yaka. 2022. “N-Oleoyl Glycine and Its Derivatives Attenuate the Acquisition and Expression of Cocaine-Induced Behaviors.” Cannabis and cannabinoid research. Abstract
Introduction: The endocannabinoid system (ECS) plays a key modulatory role during synaptic plasticity and homeostatic processes in the brain and plays an important role in the neurobiological processes underlying drug addiction. Impaired endocannabinoid (eCB) signaling contributes to dysregulated synaptic plasticity, increased stress responsivity, and craving that propel addiction. Therefore, we hypothesized that boosting the ECS by exogenous administration of selective eCBs will attenuate cocaine-induced behaviors. Materials and Methods: The behavioral paradigms included psychomotor sensitization (PS) and conditioned place preference (CPP). Liquid chromatography-mass spectrometry analysis was used for quantitative profiling of eCBs in mouse brain. Results: We first measured the levels of eCBs in different brain areas of the reward system following chronic cocaine treatment. We found that following daily administration of cocaine, the levels of N-oleoyl glycine (OlGly) were significantly elevated in the nucleus accumbens (NAc) in a region-specific manner. We next tested whether administration of OlGly will attenuate cocaine-induced behaviors. We found that administration of OlGly during withdrawal, but not during acquisition of PS, attenuated the expression of cocaine sensitization. In addition, the administration of OlGly during the acquisition of cocaine CPP, but not during withdrawal, attenuated the expression of cocaine-conditioned reward. To enhance the stability of OlGly and its duration of action, two methylated derivatives of OlGly were synthesized, the monomethylated OlGly (HU-595) and dimethylated OlGly (HU-596). We found that the effect of administration of HU-595 or HU-596 during cocaine conditioning did not differ from the OlGly-induced decrease in the expression of CPP. Conclusion: Our findings suggest that the ECS is involved in the common neurobiological mechanisms underlying the development and expression of cocaine reward and drug-seeking. Boosting the ECS exogenously has beneficial effects against cocaine-induced behaviors.
Lihi Bar-Lev Schleider, Raphael Mechoulam, Inbal Sikorin, Timna Naftali, and Victor Novack. 2022. “Adherence, Safety, and Effectiveness of Medical Cannabis and Epidemiological Characteristics of the Patient Population: A Prospective Study.” Frontiers in medicine, 9, Pp. 827849. Abstract
BACKGROUND: Despite the absence of rigorous prospective studies, there has been an increase in the use of cannabis-based medicinal products. During the study period, the use of medical cannabis in Israel was tightly regulated by national policy. Through a prospective study of approximately 10,000 patients, we aimed to characterize the medical cannabis patient population as well as to identify treatment adherence, safety, and effectiveness. METHODS AND FINDINGS: In this study of prescribed medical cannabis patients, adherence, safety, and effectiveness were assessed at 6 months. Treatment adherence was assessed by the proportion of patients purchasing the medication out of the total number of patients (excluding deceased cases and patients transferred to another cannabis clinic). Safety was assessed by the frequency of the side-effects, while effectiveness was defined as at least moderate improvement in the patient condition without treatment cessation or serious side-effects. The most frequent primary indications requiring therapy were cancer (49.1%), followed by non-specific pain (29.3%). The average age was 54.6 ± 20.9 years, 51.1% males; 30.2% of the patients reported prior experience with cannabis. During the study follow-up, 1,938 patients died (19.4%) and 1,735 stopped treatment (17.3%). Common side-effects, reported by 1,675 patients (34.2%), were: dizziness (8.2%), dry mouth (6.7%), increased appetite (4.7%), sleepiness (4.4%), and psychoactive effect (4.3%). Overall, 70.6% patients had treatment success at 6 months. Multivariable logistic regression analysis revealed that the following factors were associated with treatment success: cigarette smoking, prior experience with cannabis, active driving, working, and a young age. The main limitation of this study was the lack of data on safety and effectiveness of the treatment for patients who refused to undergo medical assessment even at baseline or died within the first 6 months. CONCLUSIONS: We observed that supervised medical-cannabis treatment is associated with high adherence, improvement in quality of life, and a decrease in pain level with a low incidence of serious adverse events.
Introduction: Cancer patients report nausea as a side effect of their chemotherapy treatment. Using the pre-clinical rodent model of acute nausea-lithium chloride (LiCl)-induced conditioned gaping-our group has demonstrated that exogenous cannabinoids may have antinausea potential. Materials and Methods: With the goal of evaluating the role of sex as a factor in pre-clinical research, we first compared the conditioned gaping reactions produced by varying doses of LiCl in male and female rats using the taste reactivity test (Experiment 1). Results: LiCl produced dose-dependent conditioned gaping similarly in male and female rats with the highest dose (127.2 mg/kg) producing robust conditioned gaping, with this dose used in subsequent experiments. Next, we examined the antinausea potential of THC (Experiment 2), CBD (Experiment 3), cannabidiolic acid (CBDA; Experiment 4) and oleoyl alanine (OlAla; Experiment 5) in both male and female rats. THC, CBD, CBDA, and OlAla dose dependently reduced conditioned gaping in both male and female rats in a similar manner. Conclusions: These results suggest that cannabinoids may be equally effective in treating nausea in both males and females.
Erin M Rock, Cheryl L Limebeer, Reem Smoum, Raphael Mechoulam, and Linda A Parker. 2022. “Effect of oleoyl glycine and oleoyl alanine on lithium chloride induced nausea in rats and vomiting in shrews.” Psychopharmacology, 239, 2, Pp. 377–383. Abstract
RATIONALE: The fatty acid amide oleoyl glycine (OlGly) and its more stable methylated form oleoyl alanine (OlAla) reduce naloxone-precipitated morphine withdrawal (MWD)-induced conditioned gaping (nausea) responses in rats. In addition, OlGly has been shown to reduce lithium chloride (LiCl)-induced conditioned gaping in rats and vomiting in Suncus murinus (house musk shrews). OBJECTIVES: Here, we compared the potential of these fatty acid amides to maintain their anti-nausea/anti-emetic effect over a delay. The following experiments examined the potential of a wider dose range of OlGly and OlAla to interfere with (1) LiCl-induced conditioned gaping in rats and (2) LiCl-induced vomiting in shrews, when administered 20 or 70 min prior to illness. RESULTS: OlAla (1, 5, 20 mg/kg) reduced LiCl-induced conditioned gaping, with OlGly only effective at the high dose (20 mg/kg), with no effect of pretreatment delay time. At the high dose of 20 mg/kg, OlGly increased passive drips during conditioning suggesting a sedative effect. In shrews, both OlGly and OlAla (1, 5 mg/kg) suppressed LiCl-induced vomiting, with no effect of pretreatment delay. OlAla more effectively suppressed vomiting, with OlAla (5 mg/kg) also increasing the latency to the first vomiting reaction. CONCLUSIONS: OlAla was more effective than OlGly in reducing both LiCl-induced gaping in rats and LiCl-induced vomiting in shrews. These findings provide further evidence that these fatty acid amides may be useful treatments for nausea and vomiting, with OlAla demonstrating superior efficacy.
Raphael Mechoulam. 2022. “A Delightful Trip Along the Pathway of Cannabinoid and Endocannabinoid Chemistry and Pharmacology.” Annual review of pharmacology and toxicology. Abstract
After a traumatic childhood in Europe during the Second World War, I found that scientific research in Israel was a pleasure beyond my expectations. Over the last 65 year, I have worked on the chemistry and pharmacology of natural products. During the last few decades, most of my research has been on plant cannabinoids, the endogenous cannabinoids arachidonoyl ethanolamide (anandamide) and 2-arachidonoyl glycerol, and endogenous anandamide-like compounds, all of which are involved in a wide spectrum of physiological reactions. Two plant cannabinoids, $Δ$(9)-tetrahydrocannabinol and cannabidiol, are approved drugs. However, the endogenous cannabinoids and the anandamide-like constituents have not yet been well investigated in humans. For me, intellectual freedom-the ability to do research based on my own scientific interests-has been the most satisfying part of my working life. Looking back over the 91 years of my long life, I conclude that I have been lucky, very lucky, both personally and scientifically. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 63 is January 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
F. Piscitelli, F. Guida, L. Luongo, F.A. Iannotti, S. Boccella, R. Verde, A. Lauritano, R. Imperatore, R. Smoum, L. Cristino, A.H. Lichtman, L.A. Parker, R. Mechoulam, S. Maione, and V. Di Marzo. 2020. “Protective Effects of N-Oleoylglycine in a Mouse Model of Mild Traumatic Brain Injury.” ACS Chemical Neuroscience, 11, 8, Pp. 1117-1128. Publisher's Version Abstract
Traumatic brain injury (TBI) is one of the main causes of death in young people for which currently no efficacious treatment exists. Recently, we have reported that mice with mild-TBI with a specific injury in the insula showed elevated levels of a little investigated N-acyl amino acid, N-oleoylglycine (OlGly). N-acyl amino acids have recently experienced an increased interest because of their important biological activities. They belong to the endocannabinoidome family of lipids with structural similarities with the endocannabinoids (eCBs). The aim of this study was to test the neuroprotective and antihyperalgesic actions of OlGly in a model of mouse mild-TBI (mTBI) and its effect on levels of eCBs and N-acylethanolamines at the end of treatment. Following mTBI, mice were administered a daily injection of OlGly (10-50-100 mg/kg i.p.) for 14 days. Treatment with OlGly normalized motor impairment and behavior in the light/dark box test, ameliorated TBI-induced thermal hyperalgesia and mechanical allodynia, and normalized aggressiveness and depression. Moreover, levels of eCBs and some N-acylethanolamines underwent significant changes 60 days after TBI, especially in the prefrontal cortex and hypothalamus, and OlGly reversed some of these changes. In conclusion, our findings reveal that OlGly ameliorates the behavioral alterations associated with mTBI in mice, while concomitantly modulating eCB and eCB-like mediator tone. © 2020 American Chemical Society.
E.M. Rock, M.T. Sullivan, S.A. Collins, H. Goodman, C.L. Limebeer, R. Mechoulam, and L.A. Parker. 2020. “Evaluation of repeated or acute treatment with cannabidiol (CBD), cannabidiolic acid (CBDA) or CBDA methyl ester (HU-580) on nausea and/or vomiting in rats and shrews.” Psychopharmacology, 237, 9, Pp. 2621-2631. Publisher's Version Abstract
Rationale: When acutely administered intraperitoneally, the non-psychoactive cannabinoid cannabidiol (CBD), its acidic precursor cannabidiolic acid (CBDA) and a stable methyl ester of CBDA (HU-580) reduce lithium chloride (LiCl)–induced conditioned gaping in male rats (a selective preclinical model of acute nausea) via activation of the serotonin 1A (5-HT1A) receptor. Objectives: To utilise these compounds to manage nausea in the clinic, we must determine if their effectiveness is maintained when injected subcutaneously (s.c) and when repeatedly administered. First, we compared the effectiveness of each of these compounds to reduce conditioned gaping following repeated (7-day) and acute (1-day) pretreatments and whether these anti-nausea effects were mediated by the 5-HT1A receptor. Next, we assessed whether the effectiveness of these compounds can be maintained when administered prior to each of 4 conditioning trials (once per week). We also evaluated the ability of repeated CBD (7 days) to reduce LiCl-induced vomiting in Suncus murinus. Finally, we examined whether acute CBD was equally effective in male and female rats. Results: Both acute and repeated (7 day) s.c. administrations of CBD (5 mg/kg), CBDA (1 μg/kg) and HU-580 (1 μg/kg) similarly reduced LiCl-induced conditioned gaping, and these effects were blocked by 5HT1A receptor antagonism. When administered over 4 weekly conditioning trials, the anti-nausea effectiveness of each of these compounds was also maintained. Repeated CBD (5 mg/kg, s.c.) maintained its anti-emetic efficacy in S. murinus. Acute CBD (5 and 20 mg/kg, s.c.) administration reduced LiCl-induced conditioned gaping similarly in male and female rats. Conclusion: When administered repeatedly (7 days), CBD, CBDA and HU-580 did not lose efficacy in reducing nausea and continued to act via agonism of the 5-HT1A receptor. When administered across 4 weekly conditioning trials, they maintained their effectiveness in reducing LiCl-induced nausea. Repeated CBD also reduced vomiting in shrews. Finally, CBD’s anti-nausea effects were similar in male and female rats. This suggests that these cannabinoids may be useful anti-nausea and anti-emetic treatments for chronic conditions, without the development of tolerance. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
E. Murillo-Rodríguez, G. Arankowsky-Sandoval, R.G. Pertwee, L. Parker, and R. Mechoulam. 2020. “Sleep and neurochemical modulation by cannabidiolic acid methyl ester in rats.” Brain Research Bulletin, 155, Pp. 166-173. Publisher's Version Abstract
Cannabidiolic acid methyl ester (HU-580) is a more stable compound than cannabidiolic acid (CBDA) which has been shown to be effective in reducing nausea, anxiety, depression behaviors in animal models. Here we extend the investigation of this compound to determine its effect on the sleep-wake cycle in male Wistar rats. HU-580 dose-dependently (0.1, 1.0 or 100 μg/Kg, i.p.) prolonged wakefulness (W) and decreased slow wave sleep (SWS) duration whereas rapid eye movement sleep (REMS) showed no statistical change. In addition, the brain microdialysis probes either placed at nucleus accumbens (NAc) or into the basal forebrain in freely moving animals were used to evaluate the effects of HU-580 treatment on neurotransmitters related to the sleep-wake cycle modulation. HU-580 enhanced extracellular levels of dopamine, serotonin collected from NAc while adenosine and acetylcholine were increased in basal forebrain. In summary, HU-580 seems to possess wake-promoting pharmacological properties and enhances the levels of wake-related neurochemicals. This is the first report of effects of HU-580 on sleep modulation expanding the very limited existent data on the neurobiological effects of HU-580 on rats. © 2019 Elsevier Inc.
E.M. Rock, S.M. Ayoub, C.L. Limebeer, A. Gene, K.L. Wills, M.V. DeVuono, R. Smoum, V. Di Marzo, A.H. Lichtman, R. Mechoulam, and L.A. Parker. 2020. “Acute naloxone-precipitated morphine withdrawal elicits nausea-like somatic behaviors in rats in a manner suppressed by N-oleoylglycine.” Psychopharmacology, 237, 2, Pp. 375-384. Publisher's Version Abstract
Rationale: Acute naloxone-precipitated morphine withdrawal (MWD) produces a conditioned place aversion (CPA) in rats even after one or two exposures to high-dose (20 mg/kg, sc) morphine followed 24-h later by naloxone (1 mg/kg, sc). However, the somatic withdrawal reactions produced by acute naloxone-precipitated MWD in rats have not been investigated. A recently discovered fatty acid amide, N-oleoylglycine (OlGly), which has been suggested to act as a fatty acid amide hydrolase (FAAH) inhibitor and as a peroxisome proliferator-activated receptor alpha (PPARα) agonist, was previously shown to interfere with a naloxone-precipitated MWD-induced CPA in rats. Objectives: The aims of these studies were to examine the somatic withdrawal responses produced by acute naloxone-precipitated MWD and determine whether OlGly can also interfere with these responses. Results: Here, we report that following two exposures to morphine (20 mg/kg, sc) each followed by naloxone (1 mg/kg, sc) 24 h later, rats display nausea-like somatic reactions of lying flattened on belly, abdominal contractions and diarrhea, and display increased mouthing movements and loss of body weight. OlGly (5 mg/kg, ip) interfered with naloxone-precipitated MWD-induced abdominal contractions, lying on belly, diarrhea and mouthing movements in male Sprague–Dawley rats, by both a cannabinoid 1 (CB1) and a PPARα mechanism of action. Since these withdrawal reactions are symptomatic of nausea, we evaluated the potential of OlGly to interfere with lithium chloride (LiCl)-induced and MWD-induced conditioned gaping in rats, a selective measure of nausea; the suppression of MWD-induced gaping reactions by OlGly was both CB1 and PPARα mediated. Conclusion: These results suggest that the aversive effects of acute naloxone-precipitated MWD reflect nausea, which is suppressed by OlGly. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.