Chronic edible dosing of Δ9-tetrahydrocannabinol (THC) in nonhuman primates reduces systemic platelet activity and function.

Cannabis usage has steadily increased as acceptance is growing for both medical and recreational reasons. Medical cannabis is administered for treatment of chronic pain based on the premise that the endocannabinoid system signals desensitize pain sensor neurons and produce anti-inflammatory effects. The major psychoactive ingredient of cannabis is Δ9-tetrahydrocannabinol (THC) that signals mainly through cannabinoid receptor-1 (CBr), which is also present on nonneuron cells including blood platelets of the circulatory system. In vitro, CBr-mediated signaling has been shown to acutely inhibit platelet activation downstream of the platelet collagen receptor glycoprotein (GP)VI. The systemic effects of chronic THC administration on platelet activity and function remain unclear. This study investigates the effects of chronic THC administration on platelet function using a nonhuman primate (NHP) model. Our results show that female and male NHPs consuming a daily THC edible had reduced platelet adhesion, aggregation, and granule secretion in response to select platelet agonists. Furthermore, a change in bioactive lipids (oxylipins) was observed in the female cohort after THC administration. These results indicate that chronic THC edible administration desensitized platelet activity and function in response to GPVI- and G-protein coupled receptor-based activation by interfering with primary and secondary feedback signaling pathways. These observations may have important clinical implications for patients who use medical marijuana and for providers caring for these patients.

Cannabinoid Receptor-2 Activation in Keratinocytes Contributes to Elevated Peripheral ß-Endorphin Levels in Patients With Obstructive Jaundice.

BACKGROUND: Cholestatic diseases are often accompanied by elevated plasma levels of endogenous opioid peptides, but it is still unclear whether central or peripheral mechanisms are involved in this process, and little is known about the change of pain threshold in these patients. The purpose of this study was to determine the preoperative pain threshold, postoperative morphine consumption, and central and peripheral ß-endorphin levels in patients with obstructive jaundice. This study also tests the hypothesis that activation of the cannabinoid receptor-2 (CB2R) in skin keratinocytes by endocannabinoids is the mechanism underlying circulating ß-endorphin elevation in patients with obstructive jaundice. METHODS: The electrical pain thresholds, 48-hour postoperative morphine consumption, concentrations of ß-endorphin in plasma and cerebrospinal fluid, skin and liver ß-endorphin expression, and plasma levels of endocannabinoids were measured in jaundiced (n = 32) and control (n = 32) patients. Male Sprague-Dawley rats and human keratinocytes (human immortalized keratinocyte cell line [HaCaT]) were used for the in vivo and in vitro experiments, respectively. Mechanical and thermal withdrawal latency, plasma level, and skin expression of ß-endorphin were measured in CB2R-antagonist-treated and control bile duct-ligated (BDL) rats. In cultured keratinocytes, the effect of CB2R agonist AM1241-induced ß-endorphin expression was observed and the phosphorylation of extracellular-regulated protein kinases 1/2, p38, and signal transducer and activator of transcription (STAT) pathways were investigated. RESULTS: This study found (1) the plasma level of ß-endorphin (mean ± standard error of the mean [SEM]) was 193.9 ± 9.6 pg/mL in control patients, while it was significantly increased in jaundiced patients (286.6 ± 14.5 pg/mL); (2) the electrical pain perception threshold and the electrical pain tolerance threshold were higher in patients with obstructive jaundice compared with controls, while the 48-hour postoperative morphine consumption was lower in the jaundiced patients; (3) there was no correlation between plasma ß-endorphin levels, electrical pain thresholds, and 48-hour postoperative morphine consumption in patients with obstructive jaundice; (4) the plasma level of the endogenous cannabinoid anandamide was increased in the jaundiced patients; (5) CB2R antagonist treatment of the BDL rats reduced ß-endorphin levels in plasma and skin keratinocytes, while it did not alter the nociceptive thresholds in BDL and control rats; (6) the endocannabinoid anandamide-induced ß-endorphin synthesis and release via CB2R in cultured keratinocytes; and (7) phosphorylation of extracellular-regulated protein kinases 1/2 is involved in the CB2R-agonist-induced ß-endorphin expression in keratinocytes. CONCLUSIONS: CB2R activation in keratinocytes by the endocannabinoid anandamide may play an important role in the peripheral elevation of ß-endorphin during obstructive jaundice.

The Activation of Cannabinoid Type-2 Receptor with JWH-133 Protects Uterine Ischemia/Reperfusion-Induced Damage.

INTRODUCTION: Uterus transplantation is a complex surgical procedure. Uterine ischemia/reperfusion (IR) damage occurring in this process may cause loss of function in the uterus. Cell damage must be prevented for a healthy uterine function and successful transplantation. Cannabinoids, with their increasing clinical use, are substances with strong anti-inflammatory and antioxidative effects and have a role in immune system regulation. However, their efficacy in uterine IR damage is still unknown. This study provides information on the potential applications cannabinoids agonist JWH-133 in uterine IR damage and, hence, in the transplant process. METHODS: Rats were divided into 4 groups (n = 8), performed uterine IR, and treated 2 groups with JWH-133. After anesthesia, ischemia was applied for 1 h to the uterus while reperfusion was applied for 3 h. After the experiment, malondialdehyde (MDA) levels and phosphorylated nuclear factor-kappa B (p-NF-κB) expression were examined in the tissue samples. Also, cell damage was evaluated by histopathological imaging and TUNEL staining. RESULTS: In the uterine IR group, NF-κB expression and MDA levels were detected at high levels. Histopathological examinations and TUNEL staining revealed extensive cell damage. On the other hand, in groups treated with JWH-133, dose-dependent NF-κB expression and MDA levels decreased (p < 0.05). Depending on the dose, the rate of surviving cells increased in TUNEL staining results. CONCLUSION: The results showed that JWH-133 was effective in reducing uterine IR damage. Cannabinoids may be a new alternative that may be used in the transplantation process in the future.

CB2 receptor-selective agonists as candidates for targeting infection, inflammation, and immunity in SARS-CoV-2 infections.

The COVID-19 pandemic caused by SARS-CoV-2 is a deadly disease afflicting millions. The pandemic continues affecting population due to nonavailability of drugs and vaccines. The pathogenesis and complications of infection mainly involve hyperimmune-inflammatory responses. Thus, therapeutic strategies rely on repurposing of drugs aimed at reducing infectivity and inflammation and modulate immunity favourably. Among, numerous therapeutic targets, the endocannabinoid system, particularly activation of cannabinoid type-2 receptors (CB2R) emerged as an important one to suppress the hyperimmune-inflammatory responses. Recently, potent antiinflammatory, antiviral and immunomodulatory properties of CB2R selective ligands of endogenous, plant, and synthetic origin were showed mediating CB2R selective functional agonism. CB2R activation appears to regulate numerous signaling pathways to control immune-inflammatory mediators including cytokines, chemokines, adhesion molecules, prostanoids, and eicosanoids. Many CB2R ligands also exhibit off-target effects mediating activation of PPARs, opioids, and TRPV, suggestive of adjuvant use with existing drugs that may maximize efficacy synergistically and minimize therapeutic doses to limit adverse/ side effects. We hypothesize that CB2R agonists, due to immunomodulatory, antiinflammatory, and antiviral properties may show activity against COVID-19. Based on the organoprotective potential, relative safety, lack of psychotropic effects, and druggable properties, CB2R selective ligands might make available promising candidates for further investigation.

Semiquantitative Activity-Based Detection of JWH-018, a Synthetic Cannabinoid Receptor Agonist, in Oral Fluid after Vaping.

The rapid proliferation of new synthetic cannabinoid receptor agonists (SCRAs) has initiated considerable interest in the development of so-called "untargeted" screening strategies. One of these new screening technologies involves the activity-based detection of SCRAs. In this study, we evaluated whether (synthetic) cannabinoid activity can be detected in oral fluid (OF) and, if so, whether it correlates with SCRA concentrations. OF was collected at several time points in a placebo-controlled JWH-018 administration study. The outcome of the cell-based cannabinoid reporter system, which monitored the cannabinoid receptor activation, was compared to the quantitative data for JWH-018, obtained via a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. A total of 175 OF samples were collected and analyzed via both methods. The cannabinoid reporter assay correctly classified the vast majority of the samples as either negative (<0.25 ng/mL; 74/75 = 99%) or having low (0.25-1.5 ng/mL; 16/16 = 100% and 1.5-10 ng/mL; 37/41 = 90%), mid (10-100 ng/mL; 23/25 = 92%) or high (>100 ng/mL; 16/18 = 89%) JWH-018 concentrations. Passing-Bablok regression analysis yielded a good linear correlation, with no proportional difference between both methods (slope 0.97; 95% confidence interval 0.86-1.14) and only a small systematic difference. This is the first study to demonstrate the applicability of an untargeted, activity-based approach for SCRA detection in OF. Additionally, the outcome of the cannabinoid reporter assay was compared to the gold standard (LC-MS/MS), showing a good correlation between both methods, indicating that the cannabinoid reporter assay can be used for an estimation of drug concentrations.

Heteromer formation between cannabinoid type 1 and dopamine type 2 receptors is altered by combination cannabinoid and antipsychotic treatments.

The cannabinoid type 1 (CB1 ) receptor and the dopamine type 2 (D2 ) receptor are co-localized on medium spiny neuron terminals in the globus pallidus where they modulate neural circuits involved in voluntary movement. Physical interactions between the two receptors have been shown to alter receptor signaling in cell culture. The objectives of the current study were to identify the presence of CB1 /D2 heteromers in the globus pallidus of C57BL/6J male mice, define how CB1 /D2 heteromer levels are altered following treatment with cannabinoids and/or antipsychotics, and determine if fluctuating levels of CB1 /D2 heteromers have functional consequences. Using in situ proximity ligation assays, we observed CB1 /D2 heteromers in the globus pallidus of C57BL/6J mice. The abundance of the heteromers increased following treatment with the nonselective cannabinoid receptor agonist, CP55,940. In contrast, treatment with the typical antipsychotic haloperidol reduced the number of CB1 /D2 heteromers, whereas the atypical antipsychotic olanzapine treatment had no effect. Co-treatment with CP55,940 and haloperidol had similar effects to haloperidol alone, whereas co-treatment with CP55,940 and olanzapine had similar effects to CP55,940. The observed changes were found to have functional consequences as the differential effects of haloperidol and olanzapine also applied to γ-aminobutyric acid release in STHdhQ7/Q7 cells and motor function in C57BL/6J male mice. This work highlights the clinical relevance of co-exposure to cannabinoids and different antipsychotics over acute and prolonged time periods.

Cannabinoid Antagonist Drug Discrimination in Nonhuman Primates.

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.

Cannabinoid agonist administration within the cerebellar cortex impairs motor learning.

Systemic administration of cannabinoid agonists impairs cerebellum-dependent motor learning. The cannabinoid-induced impairment of motor learning has been hypothesized to be due to disruption of Purkinje cell plasticity within the cerebellar cortex. In the current study, we tested this hypothesis in rats with localized microinfusions of cannabinoid agonists and antagonists into the cerebellar cortex during eyeblink conditioning, a type of cerebellum-dependent motor learning. Infusions of the cannabinoid agonists WIN55,212-2 or ACEA directly into the eyeblink conditioning microzone of the cerebellar cortex severely impaired acquisition of eyeblink conditioning, whereas the CB1R antagonist SR141716A did not produce a significant impairment. Infusions of WIN55,212-2 outside of the eyeblink conditioning microzone did not impair motor learning, establishing anatomical specificity for the agonist effects. The motor learning impairment caused by WIN55,212-2 and ACEA was rescued by SR141716A, indicating that the learning deficit was produced through CB1Rs. The current findings demonstrate that the effects of cannabinoid receptor agonists on motor learning are localized to CB1Rs within a discrete microzone of the cerebellar cortex.

Psychosis-Relevant Effects of Intravenous Delta-9-Tetrahydrocannabinol: A Mega Analysis of Individual Participant-Data from Human Laboratory Studies.

INTRODUCTION: There is increasing interest in the relationship between cannabinoids and psychosis. While individual human laboratory studies have been critical in demonstrating that cannabinoids (e.g., delta-9-tetrahydrocannabinol [THC]) can induce acute transient psychosis-like effects in healthy human volunteers, combining data from multiple studies offers a fine-grained view of these effects. METHODS: THC-induced psychosis-relevant effects were examined using a data repository of 10 double-blind, randomized, placebo-controlled, crossover studies with 400 i.v. THC infusions in healthy human volunteers. The Positive and Negative Syndrome scale was used to measure psychotomimetic effects. The profile of symptoms, frequency of a response, its relationship to THC dose and substance use, latent structure in Positive and Negative Syndrome scale response, and the relationships between psychotomimetic and perceptual alteration symptoms were evaluated. RESULTS: Clinically meaningful increases in positive symptoms were noted in 44.75% infusions; conceptual disorganization, hallucinations, blunted affect, somatic concern, motor retardation, and poor attention were the items most frequently altered by THC. The increase in Positive and Negative Syndrome scale positive symptoms was positively associated with THC dose (beta = 11.13, SE = 4.94, Wald χ 2 = 19.88, P < .001) and negatively associated with frequent cannabis use (beta = -0.575, SE = 0.14, Wald χ 2 = 18.13, P < .001). Furthermore, positive symptoms were strongly correlated with Clinician Administered Dissociative States Scale perceptual alterations score (rs = 0.514, P < .001). CONCLUSION: Intravenous administration of THC consistently induces psychotomimetic effects that include symptoms across Positive and Negative Syndrome scale domains. Moreover, healthy individuals who frequently use cannabis have a blunted psychotomimetic response.

Adolescent Exposure to WIN 55212-2 Render the Nigrostriatal Dopaminergic Pathway Activated During Adulthood.

BACKGROUND: During adolescence, neuronal circuits exhibit plasticity in response to physiological changes and to adapt to environmental events. Nigrostriatal dopaminergic pathways are in constant flux during development. Evidence suggests a relationship between early use of cannabinoids and psychiatric disorders characterized by altered dopaminergic systems, such as schizophrenia and addiction. However, the impact of adolescent exposure to cannabinoids on nigrostriatal dopaminergic pathways in adulthood remains unclear. The aim of this research was to determine the effects of repeated activation of cannabinoid receptors during adolescence on dopaminergic activity of nigrostriatal pathways and the mechanisms underlying this impact during adulthood. METHODS: Male Sprague-Dawley rats were treated with 1.2 mg/kg WIN 55212-2 daily from postnatal day 40 to 65. Then no-net flux microdialysis of dopamine in the dorsolateral striatum, electrophysiological recording of dopaminergic neuronal activity, and microdialysis measures of gamma-aminobutyric acid (GABA) and glutamate in substantia nigra par compacta were carried out during adulthood (postnatal days 72-78). RESULTS: Repeated activation of cannabinoid receptors during adolescence increased the release of dopamine in dorsolateral striatum accompanied by increased population activity of dopamine neurons and decreased extracellular GABA levels in substantia nigra par compacta in adulthood. Furthermore, perfusion of bicuculline, a GABAa antagonist, into the ventral pallidum reversed the increased dopamine neuron population activity in substantia nigra par compacta induced by adolescent cannabinoid exposure. CONCLUSIONS: These results suggest that adolescent exposure to cannabinoid agonists produces disinhibition of nigrostriatal dopamine transmission during adulthood mediated by decreased GABAergic input from the ventral pallidum.

Electronic cigarettes and e-cigarette/vaping product use associated lung injury (EVALI).

Electronic cigarettes (e-cigarettes) are noncombustible tobacco products that have been promoted as safer alternatives to conventional cigarettes and beneficial tools for smoking cessation. However, e-cigarettes have been shown to produce aerosols with high concentrations of propylene glycol, glycerol, volatile organic compounds, and free radicals, which can lead to lung damage. Furthermore, e-cigarettes can deliver nicotine at concentrations higher than traditional combustibles, making them highly addictive. As delivery devices became smaller, less expensive, and refillable, the use of e-cigarettes dramatically increased, especially among adolescents and young adults in the United States. This rise in popularity of noncombustible products led to an outbreak of e-cigarette or vaping product use-associated lung injury (EVALI) in the fall of 2019. In this article, we review the history of e-cigarettes and its prevalence among American youth, the EVALI outbreak and clinical presentation of EVALI patients, and recent legislative efforts to regulate e-cigarette use.

The use of medical grade cannabis in Italy for drug-resistant epilepsy: a case series.

In Italy, medical grade cannabis (MGC) can be prescribed for different medical conditions, including drug-resistant epilepsy (DRE), once standard and approved therapies have failed, or caused non-tolerable side effects. Here, we present a retrospective case series report of five patients with DRE who started therapy with MGC. Authorized ISO 9001:2008 pharmacies prepared MGC according to Italian laws. Olive oil extracts (OOEs) were prepared following standard extraction protocols, and cannabinoids were measured on each OOE to check for successful extraction.After treatment with MGC, all patients reported a reduction in seizure frequency and severity, and some reported improved mood, sleep quality, and general well-being without relevant side effects. Despite the small sample size and open-label nature of the data, we show that MGC may be successfully used to treat DRE. This is especially true when considering that no valid therapeutic option exists for these patients and that MGC was extremely well tolerated.

Different pharmaceutical preparations of Δ9 -tetrahydrocannabinol differentially affect its behavioral effects in rats.

Based on the contribution of the endocannabinoid system to the pathophysiology of schizophrenia, the primary pro-psychotic ingredient of Cannabis sativa, Δ-9-tetrahydrocannabinol (Δ-9-THC), is used in preclinical as well as clinical research to mimic schizophrenia-like symptoms. While it is common to administer lipid-based formulations of Δ-9-THC in human studies orally, intraperitoneal injections of water-based solutions are used in animal models. Because of the poor water solubility of Δ-9-THC, solubilizers such as ethanol and/or emulsifiers are needed for these preparations. In order to test whether a lipid-based solvent would be superior over a water-based vehicle in rats, we compared the effects on locomotor activity and prepulse inhibition (PPI) of the acoustic startle reaction, as well as pharmacokinetic data obtained from rats' serum and brain tissue samples. Up to 50 mg/kg Δ-9-THC in the lipid-based formulation was not able to induce any behavioral alterations, while already 5 mg/kg of the water-based Δ-9-THC preparation significantly reduced locomotor activity. This also induced a small but significant PPI reduction, which was prepulse intensity dependent. Interestingly, the reflexive motor response to the startle stimulus was not affected by the water-based Δ-9-THC solution. Analysis of serum and brain Δ-9-THC levels by high-performance liquid chromatography/mass spectrometry revealed that although the final concentration reached in the brain was comparable for both pharmaceutical preparations, the water-based formulation achieved a faster kinetic. We, therefore, conclude that the slope of the Δ-9-THC concentration-time curve and the resulting cannabinoid receptor type 1 activation per time unit are responsible for the induction of behavioral alterations.

The loss of NMDAR-dependent LTD following cannabinoid self-administration is restored by positive allosteric modulation of CB1 receptors.

Glutamatergic plasticity in the nucleus accumbens core (NAcore) is a key neuronal process in appetitive learning and contributes to pathologies such as drug addiction. Understanding how this plasticity factors into cannabis addiction and relapse has been hampered by the lack of a rodent model of cannabis self-administration. We used intravenous self-administration of two constituents of cannabis, Δ9 -tetrahydrocannabinol (THC) and cannabidiol (CBD) to examine how contingent cannabis use and cue-induced cannabinoid-seeking alters glutamatergic neurotransmission and synaptic plasticity in NAcore. NMDA receptor (NMDAR)-dependent long-term depression (LTD) in the NAcore was lost after cannabinoid, but not sucrose self-administration. Surprisingly, when rats underwent cue-induced cannabinoid seeking, LTD was restored. Loss of LTD was accompanied by desensitization of cannabinoid receptor 1 (CB1R). CB1R are positioned to regulate synaptic plasticity by being expressed on glutamatergic terminals and negatively regulating presynaptic excitability and glutamate release. Supporting this possibility, LTD was restored by promoting CB1R signaling with the CB1 positive allosteric modulator GAT211. These data implicate NAcore CB1R as critical regulators of metaplasticity induced by cannabis self-administration and the cues predicting cannabis availability.

Activation of the cannabinoid receptor 2 increases renal perfusion.

Acute kidney injury (AKI) is an increasing clinical problem that is associated with chronic kidney disease progression. Cannabinoid receptor 2 (CB2) activation has been shown to mitigate some of the deleterious tubular effects due to AKI, but its role on the renal vasculature has not been fully described. In this study, we investigated the effects of our novel CB2 receptor agonist, SMM-295, on renal vasculature by assessing cortical perfusion with laser Doppler flowmetry and changes in luminal diameter with isolated afferent arterioles. In this study, intravenously infused SMM-295 (6 mg/kg) significantly increased cortical renal perfusion (13.8 ± 0.6%; P < 0.0001; n = 7) compared with vehicle (0.1 ± 1.5%; n = 10) normalized to baseline values in anesthetized C57BL/6J mice. This effect was not dependent upon activation of the CB1 receptor (met-anandamide; 6 mg/kg iv) and was predominantly abolished in Cnr2 knockout mice with SMM-295 (6 mg/kg iv). Ablation of the renal afferent nerves with capsaicin blocked the SMM-295-dependent increase in renal cortical perfusion, and the increased renal blood flow was not dependent upon products synthesized by cyclooxygenase or nitric oxide synthase. The increased renal perfusion by CB2 receptor activation is also attributed to a direct vascular effect, since SMM-295 (5 µM) engendered a significant 37 ± 7% increase ( P < 0.0001; n = 4) in luminal diameters of norepinephrine-preconstricted afferent arterioles. These data provide new insight into the potential benefit of SMM-295 by activating vascular and nonvascular CB2 receptors to promote renal vasodilation, and provide a new therapeutic target to treat renal injuries that impact renal blood flow dynamics.

The effects of delta-9-tetrahydrocannabinol on Krüppel-like factor-4 expression, redox homeostasis, and inflammation in the kidney of diabetic rat.

Diabetes mellitus is a complex, multifactorial disorder that is attributed to pancreatic ß cell dysfunction. Pancreatic ß cell dysfunction results in declining utilization of glucose by peripheral tissues as kidney and it leads to nephropathy. Excessive production and accumulation of free radicals and incapable antioxidant defense system lead to impaired redox status. Macromolecular damage may occur due to impaired redox status and also immune imbalance. Δ9-Tetrahydrocannabinol (THC) is the main active ingredient in cannabis. THC acts as an immunomodulator and an antioxidant agent. Our aim was to evaluate the effects of THC in the diabetic kidney. We analyzed macromolecular damage biomarkers as protein carbonyl (PCO), lipid hydroperoxide (LHP), malondialdehyde (MDA), 8-hydroxy-2'-deoxyguanosine (8-OHdG), and antioxidant defense system biomarkers as thiol fractions (T-SH, NP-SH, P-SH) and Cu/Zn-superoxide dismutase activity for the antioxidative effects of THC. Furthermore, mRNA expression of Krüppel-like factor-4, secreted immunopositive cell number changes of interleukin-6, nuclear factor κß (NF-κß), and peroxisome proliferator-activated receptor-γ and tumor necrosis factor α (TNF-α) levels were analyzed for the immunomodulatory activity of THC. Diabetic rats showed significantly increased levels of PCO, LHP, MDA, and 8-OHdG when compared with controls (P < 0.05 for each parameter). THC significantly reduced the elevated levels of PCO and 8-OHdG (P < 0.05 for both parameters) and also LHP and MDA levels were insignificantly reduced by THC. Also, thiol fractions insignificantly increased in THC administered diabetic kidney when compared with diabetic rats. The NF-κß cell number significantly decreased in the diabetic rats treated with THC compared with the diabetic group. According to our data, THC has ameliorative effects on the impaired redox status of diabetic kidney and also it acts as an immunomodulator. Therefore, THC might be used as a therapeutic agent for diabetic kidneys but its usage in the healthy kidney may show adverse effects.

Developmental and behavioral effects in neonatal and adult mice following prenatal activation of endocannabinoid receptors by capsaicin.

Despite the apparent abundance of ligand-gated transient receptor potential vanilloid type 1 (TRPV1) and possible cross talk between the endocannabinoid and endovanilloid systems in the central nervous system (CNS), it is unclear what role TRPV1 receptor activation in CNS plays in neurobehavioral development. We previously reported that capsaicin or WIN55212-2 induces risk aversion in the plus-maze test, which was dependent on the gender and mouse strain used. In this study, pregnant BALBc mice were administered capsaicin (1.0 or 4.0 mg/kg, i.p.) during the second week of gestation. Developmental effects of prenatal exposure to capsaicin were assessed in neonates, and behavioral effects were assessed in adult offspring. Gender- and dose-specific variations in ultrasonic vocalizations, weight gain, righting reflex, and general activity of the pups were observed. Prenatal exposure to capsaicin altered plus-maze performance, especially with further exogenous capsaicin challenge. Furthermore, dose- and gender-specific effects were evident in the conditioned place preference/aversion paradigm following conditioning with capsaicin in adult animals. The capsaicin-induced aversion in the plus-maze test was enhanced by WIN55212-2 and blocked by pretreatment with vanilloid antagonist capsazepine or the CB1 receptor antagonist rimonabant, demonstrating an interaction between the endocannabinoid and endovanilloid systems in CNS. Taken together, the interaction between the endocannabinoid and endovanilloid signaling systems can be exploited for therapeutic applications in health and disease.

Beneficial and deleterious effects of cannabinoids in the brain: the case of ultra-low dose THC.

This article reviews the neurocognitive advantages and drawbacks of cannabinoid substances, and discusses the possible physiological mechanisms that underlie their dual activity. The article further reviews the neurocognitive effects of ultra-low doses of ∆9-tetrahydrocannabinol (THC; 3-4 orders of magnitude lower than the conventional doses) in mice, and proposes such low doses of THC as a possible remedy for various brain injuries and for the treatment of age-related cognitive decline.

Selective Cannabinoid 2 Receptor Agonists as Potential Therapeutic Drugs for the Treatment of Endotoxin-Induced Uveitis.

(1) Background: The cannabinoid 2 receptor (CB2R) is a promising anti-inflammatory drug target and development of selective CB2R ligands may be useful for treating sight-threatening ocular inflammation. (2) Methods: This study examined the pharmacology of three novel chemically-diverse selective CB2R ligands: CB2R agonists, RO6871304, and RO6871085, as well as a CB2R inverse agonist, RO6851228. In silico molecular modelling and in vitro cell-based receptor assays were used to verify CB2R interactions, binding, cell signaling (ß-arrestin and cAMP) and early absorption, distribution, metabolism, excretion, and toxicology (ADMET) profiling of these receptor ligands. All ligands were evaluated for their efficacy to modulate leukocyte-neutrophil activity, in comparison to the reported CB2R ligand, HU910, using an in vivo mouse model of endotoxin-induced uveitis (EIU) in wild-type (WT) and CB2R-/- mice. The actions of RO6871304 on neutrophil migration and adhesion were examined in vitro using isolated neutrophils from WT and CB2R-/- mice, and in vivo in WT mice with EIU using adoptive transfer of WT and CB2R-/- neutrophils, respectively. (3) Results: Molecular docking studies indicated that RO6871304 and RO6871085 bind to the orthosteric site of CB2R. Binding studies and cell signaling assays for RO6871304 and RO6871085 confirmed high-affinity binding to CB2R and selectivity for CB2R > CB1R, with both ligands acting as full agonists in cAMP and ß-arrestin assays (EC50s in low nM range). When tested in EIU, topical application of RO6871304 and RO6871085 decreased leukocyte-endothelial adhesion and this effect was antagonized by the inverse agonist, RO6851228. The CB2R agonist, RO6871304, decreased in vitro neutrophil migration of WT neutrophils but not neutrophils from CB2R-/-, and attenuated adhesion of adoptively-transferred leukocytes in EIU. (4) Conclusions: These unique ligands are potent and selective for CB2R and have good immunomodulating actions in the eye. RO6871304 and RO6871085, as well as HU910, decreased leukocyte adhesion in EIU through inhibition of resident ocular immune cells. The data generated with these three structurally-diverse and highly-selective CB2R agonists support selective targeting of CB2R for treating ocular inflammatory diseases.

Delta-9-tetrahydrocannabinol potentiates fear memory salience through functional modulation of mesolimbic dopaminergic activity states.

Chronic or acute exposure to delta-9-tetrahydrocannabinol (THC), the main psychoactive compound in cannabis, has been associated with numerous neuropsychiatric side-effects, including dysregulation of emotional processing and associative memory formation. Clinical and preclinical evidence suggests that the effects of THC are due to the ability to modulate mesolimbic dopamine (DA) activity states in the nucleus accumbens (NAc) and ventral tegmental area (VTA). Nevertheless, the mechanisms by which THC modulates mesolimbic DA function and emotional processing are not well understood. Using an olfactory associative fear memory procedure combined with in vivo neuronal electrophysiology, we examined the effects of direct THC microinfusions targeting the shell region of the NAc (NASh) and examined how THC may modulate the processing of fear-related emotional memory and concomitant activity states of the mesolimbic DA system. We report that intra-NASh THC dose-dependently potentiates the emotional salience of normally subthreshold fear conditioning cues. These effects were dependent upon intra-VTA transmission through GABAergic receptor mechanisms and intra-NASh DAergic transmission. Furthermore, doses of intra-NASh THC that potentiated fear memory salience were found to modulate intra-VTA neuronal network activity by increasing the spontaneous firing and bursting frequency of DAergic neurones whilst decreasing the activity levels of a subpopulation of putative GABAergic VTA neurones. These findings demonstrate that THC can act directly in the NASh to modulate mesolimbic activity states and induce disturbances in emotional salience and memory formation through modulation of VTA DAergic transmission.