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.

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.

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.

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.

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.

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.

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.

Phytocannabinoids possess a wide range of immune regulatory properties, mediated by the endocannabinoid system. Monocyte/macrophage innate immune cells express endocannabinoid receptors. Dysregulation of macrophage function is involved in the pathogenesis of different inflammatory diseases, including inflammatory bowel disease. In our research, we aimed to evaluate the effects of the phytocannabinoids D9 tetrahydrocannabinol (THC) and cannabidiol (CBD) on macrophage activation. Macrophages from young and aged C57BL/6 mice were activated in vitro in the presence of pure cannabinoids or cannabis extracts. The phenotype of the cells, nitric oxide (NO•) secretion, and cytokine secretion were examined. In addition, these treatments were administered to murine colitis model. The clinical statuses of mice, levels of colon infiltrating macrophages, and inflammatory cytokines in the blood, were evaluated. We demonstrated inhibition of macrophage NO• and cytokine secretion and significant effects on expression of cell surface molecules. In the murine model, clinical scores were improved and macrophage colon infiltration reduced following treatment. We identified higher activity of cannabis extracts as compared with pure cannabinoids. Each treatment had a unique effect on cytokine composition. Overall, our results establish that the effects of cannabinoid treatments differ. A better understanding of the reciprocal relationship between cannabinoids and immunity is essential to design targeted treatment strategies.

{Environmental heat load (HL) adversely affects the performance of dairy cows. The endocannabinoid system (ECS) regulates metabolism and the stress response, thus we hypothesized that HL may affect the ECS of dairy cows. Our objective was to determine the levels of endocannabinoids (eCBs) and gene and protein expressions of the ECS components in adipose tissue (AT) and plasma of early postpartum (PP) and late-lactation cows. In addition, we examined eCBs in milk, and studied the interaction of eCBs with bovine cannabinoids receptors CB1 and CB2. In the first experiment, plasma and AT were sampled from cows calving during summer (S

The endocannabinoid system consists mainly of 2-arachidonoylglycerol and anandamide, as well as cannabinoid receptor type 1 and type 2 (CB2). Based on previous studies, we hypothesized that a circulating peptide previously identified as osteogenic growth peptide (OGP) maintains a bone-protective CB2 tone. We tested OGP activity in mouse models and cells, and in human osteoblasts. We show that the OGP effects on osteoblast proliferation, osteoclastogenesis, and macrophage inflammation in vitro, as well as rescue of ovariectomy-induced bone loss and prevention of ear edema in vivo are all abrogated by genetic or pharmacological ablation of CB2. We also demonstrate that OGP binds at CB2 and may act as both an agonist and positive allosteric modulator in the presence of other lipophilic agonists. In premenopausal women, OGP circulating levels significantly decline with age. In adult mice, exogenous administration of OGP completely prevented age-related bone loss. Our findings suggest that OGP attenuates age-related bone loss by maintaining a skeletal CB2 tone. Importantly, they also indicate the occurrence of an endogenous peptide that signals via CB2 receptor in health and disease.

A series of novel cannabinoid-type derivatives were synthesized by the coupling of (1S,4R)-(+) and (1R,4S)-(-)-fenchones with various resorcinols/phenols. The fenchone-resorcinol derivatives were fluorinated using Selectfluor and demethylated using sodium ethanethiolate in dimethylformamide (DMF). The absolute configurations of four compounds were determined by X-ray single crystal diffraction. The fenchone-resorcinol analogs possessed high affinity and selectivity for the CB2 cannabinoid receptor. One of the analogues synthesized, 2-(2',6'-dimethoxy-4'-(2″-methyloctan-2″-yl)phenyl)-1,3,3-trimethylbicyclo[2.2.1]heptan-2-ol (1d), had a high affinity (K(i) = 3.51 nM) and selectivity for the human CB2 receptor (hCB2). In the [(35)S]GTP$\gamma$S binding assay, our lead compound was found to be a highly potent and efficacious hCB2 receptor agonist (EC(50) = 2.59 nM, E((max)) = 89.6%). Two of the fenchone derivatives were found to possess anti-inflammatory and analgesic properties. Molecular-modeling studies elucidated the binding interactions of 1d within the CB2 binding site.

Activation of the cannabinoid-1 receptor (CB(1)R) and the mammalian target of rapamycin complex 1 (mTORC1) in the renal proximal tubular cells (RPTCs) contributes to the development of diabetic kidney disease (DKD). However, the CB(1)R/mTORC1 signaling axis in the kidney has not been described yet. We show here that hyperglycemia-induced endocannabinoid/CB(1)R stimulation increased mTORC1 activity, enhancing the transcription of the facilitative glucose transporter 2 (GLUT2) and leading to the development of DKD in mice; this effect was ameliorated by specific RPTCs ablation of GLUT2. Conversely, CB(1)R maintained the normal activity of mTORC1 by preventing the cellular excess of amino acids during normoglycemia. Our findings highlight a novel molecular mechanism by which the activation of mTORC1 in RPTCs is tightly controlled by CB(1)R, either by enhancing the reabsorption of glucose and inducing kidney dysfunction in diabetes or by preventing amino acid uptake and maintaining normal kidney function in healthy conditions.

Over-activation of the endocannabinoid/CB(1)R system is a hallmark feature of obesity and its related comorbidities, most notably type 2 diabetes (T2D), and non-alcoholic fatty liver disease (NAFLD). Although the use of drugs that widely block the CB(1)R was found to be highly effective in treating all metabolic abnormalities associated with obesity, they are no longer considered a valid therapeutic option due to their adverse neuropsychiatric side effects. Here, we describe a novel nanotechnology-based drug delivery system for repurposing the abandoned first-in-class global CB(1)R antagonist, rimonabant, by encapsulating it in polymeric nanoparticles (NPs) for effective hepatic targeting of CB(1)Rs, enabling effective treatment of NAFLD and T2D. Rimonabant-encapsulated NPs (Rimo-NPs) were mainly distributed in the liver, spleen, and kidney, and only negligible marginal levels of rimonabant were found in the brain of mice treated by iv/ip administration. In contrast to freely administered rimonabant treatment, no CNS-mediated behavioral activities were detected in animals treated with Rimo-NPs. Chronic treatment of diet-induced obese mice with Rimo-NPs resulted in reduced hepatic steatosis and liver injury as well as enhanced insulin sensitivity, which were associated with enhanced cellular uptake of the formulation into hepatocytes. Collectively, we successfully developed a method of encapsulating the centrally acting CB(1)R blocker in NPs with desired physicochemical properties. This novel drug delivery system allows hepatic targeting of rimonabant to restore the metabolic advantages of blocking CB(1)R in peripheral tissues, especially in the liver, without the negative CB(1)R-mediated neuropsychiatric side effects.

Obesity is a global medical problem; its common form is known as diet-induced obesity (DIO); however, there are several rare genetic disorders, such as Prader-Willi syndrome (PWS), that are also associated with obesity (genetic-induced obesity, GIO). The currently available therapeutics for treating DIO and GIO are very limited, and they result in only a partial improvement. Cannabidiolic acid (CBDA), a constituent of Cannabis sativa, gradually decarboxylates to cannabidiol (CBD). Whereas the anti-obesity properties of CBD have been reasonably identified, our knowledge of the pharmacology of CBDA is more limited due to its instability. To stabilize CBDA, a new derivative, CBDA-O-methyl ester (HU-580, EPM301), was synthesized. The therapeutic potential of EPM301 in appetite reduction, weight loss, and metabolic improvements in DIO and GIO was tested in vivo. EPM301 (40 mg/kg/d, i.p.) successfully resulted in weight loss, increased ambulation, as well as improved glycemic and lipid profiles in DIO mice. Additionally, EPM301 ameliorated DIO-induced hepatic dysfunction and steatosis. Importantly, EPM301 (20 and 40 mg/kg/d, i.p.) effectively reduced body weight and hyperphagia in a high-fat diet-fed Magel2(null) mouse model for PWS. In addition, when given to standard-diet-fed Magel2(null) mice as a preventive treatment, EPM301 completely inhibited weight gain and adiposity. Lastly, EPM301 increased the oxidation of different nutrients in each strain. All together, EPM301 ameliorated obesity and its metabolic abnormalities in both DIO and GIO. These results support the idea to further promote this synthetic CBDA derivative toward clinical evaluation in humans.