Cannabinoid signaling and risk in Huntington’s disease

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“Dysregulated endocannabinoid (eCB) signaling and the loss of cannabinoid receptors (CB1Rs) are important phenotypes of Huntington’s disease (HD) but the precise contribution that eCB signaling has at the circuit level is unknown. Using a computational model of spiking neurons, synapses, and eCB signaling, we demonstrate that eCB signaling functions as a homeostatic control mechanism, minimizing excess glutamate. Furthermore, our model demonstrates that metabolic risk, quantified by excess glutamate, increases with cortico-striatal long-term depression (LTD) and/or increased cortico-striatal activity, and replicates a progressive loss of cannabinoid receptors on inhibitory terminals as a function of the excitatory/inhibitory ratio.”

Effects of hemp seed alone and combined with aerobic exercise on metabolic parameters, oxidative stress, and neurotrophic factors in young sedentary men

“Hemp seed and physical activity (PA) have many benefits for the metabolic and brain health of the body. This study investigated the effects of hemp seed alone and aerobic exercise on metabolic markers, oxidative stress, and neurotrophic factors in young sedentary men. This double-blind, placebo-controlled, randomized clinical trial was conducted on 48 sedentary young men in Tabriz, Iran, from April to August. The researcher in this study randomized all participants into four groups, including (1) hemp seed, (2) hemp seed + PA, (3) PA + placebo, and (4) placebo. Hemp seed supplement was administered in two 1-g capsules daily, and aerobic PA was performed a week thrice. Levels of anthropometric indices, dietary intake, antioxidant markers, lipid profile, fasting blood sugar (FBS), insulin, homeostatic model assessment for insulin resistance (HOMA-IR), quantitative insulin-sensitivity check index (QUICKI), brain-derived neurotrophic factor (BDNF), neuropeptide Y (NPY), balance, reaction time, and sit-ups were evaluated for all participants at baseline and post-intervention. We used ANOVA and ANCOVA analysis to compare oxidative stress and neurotropic factors in all intervention groups. If the distribution of the response variable was not normal, the non-parametric equivalent of these tests was used (Wilcoxon and Kruskal-Wallis tests). We performed all statistical analyzes using SPSS software version 23, and the significance level was considered 0.05 in all the statistical tests. Aerobic PA with hemp seed consumption caused a significant difference in weight, body mass index, fat mass, high-density lipoprotein, catalase, and BDNF compared with baseline. Also, aerobic PA alone caused significant changes in body weight, fat mass, and triglyceride compared with baseline. Consumption of hemp seeds alone caused a significant increase in high-density lipoprotein levels compared with baseline. At the end of the study, fat mass, total cholesterol, low-density lipoproteins, and BDNF were significantly different between the groups. According to our results, aerobic PA combined with hemp seed consumption may improve anthropometric indices, lipid profile, and BDNF and improve health outcomes like cardiovascular comorbidities, oxidative stress, and insulin resistance. PRACTICAL APPLICATIONS: A sedentary lifestyle has numerous health-threatening consequences like cardiovascular comorbidities, oxidative stress, and insulin resistance. The importance of physical activity (PA) in improving these clinical manifestations is well-known; however, the potential benefits of herbal therapy combined with PA in reducing the side effects of a sedentary lifestyle have not been well studied. In the current research, we evaluated the benefits of hemp seed alone and combined with aerobic exercise on metabolic markers, oxidative stress, and neurotrophic factors in young sedentary men for the first time. According to our results, aerobic PA combined with hemp seed consumption improved anthropometric indices, lipid profile, and brain-derived neurotrophic factor among young sedentary men.”

Modulation of type 1 cannabinoid receptor activity by cannabinoid by-products from Cannabis sativa and non-cannabis phytomolecules

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“Cannabis sativa contains more than 120 cannabinoids and 400 terpene compounds (i.e., phytomolecules) present in varying amounts. Cannabis is increasingly available for legal medicinal and non-medicinal use globally, and with increased access comes the need for a more comprehensive understanding of the pharmacology of phytomolecules. The main transducer of the intoxicating effects of Cannabis is the type 1 cannabinoid receptor (CB1R). ∆9-tetrahydrocannabinolic acid (∆9-THCa) is often the most abundant cannabinoid present in many cultivars of Cannabis. Decarboxylation converts ∆9-THCa to ∆9-THC, which is a CB1R partial agonist. Understanding the complex interplay of phytomolecules-often referred to as “the entourage effect”-has become a recent and major line of inquiry in cannabinoid research. Additionally, this interest is extending to other non-Cannabis phytomolecules, as the diversity of available Cannabis products grows. Here, we chose to focus on whether 10 phytomolecules (∆8-THC, ∆6a,10a-THC, 11-OH-∆9-THC, cannabinol, curcumin, epigallocatechin gallate, olivetol, palmitoylethanolamide, piperine, and quercetin) alter CB1R-dependent signaling with or without a co-treatment of ∆9-THC. Phytomolecules were screened for their binding to CB1R, inhibition of forskolin-stimulated cAMP accumulation, and βarrestin2 recruitment in Chinese hamster ovary cells stably expressing human CB1R. Select compounds were assessed further for cataleptic, hypothermic, and anti-nociceptive effects on male mice. Our data revealed partial agonist activity for the cannabinoids tested, as well as modulation of ∆9-THC-dependent binding and signaling properties of phytomolecules in vitro and in vivo. These data represent a first step in understanding the complex pharmacology of Cannabis– and non-Cannabis-derived phytomolecules at CB1R and determining whether these interactions may affect the physiological outcomes, adverse effects, and abuse liabilities associated with the use of these compounds.”

Yin and yang of cannabinoid CB1 receptor: CB1 deletion in immune cells causes exacerbation while deletion in non-immune cells attenuates obesity

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“While blockade of cannabinoid receptor 1 (CB1) has been shown to attenuate diet-induced obesity (DIO), its relative role in different cell types has not been tested. The current study investigated the role of CB1 in immune vs non-immune cells during DIO by generating radiation-induced bone marrow chimeric mice that expressed functional CB1 in all cells except the immune cells or expressed CB1 only in immune cells. CB1-/- recipient hosts were resistant to DIO, indicating that CB1 in non-immune cells is necessary for induction of DIO. Interestingly, chimeras with CB1-/- in immune cells showed exacerbation in DIO combined with infiltration of bone-marrow-derived macrophages to the brain and visceral adipose tissue, elevated food intake, and increased glucose intolerance. These results demonstrate the opposing role of CB1 in hematopoietic versus non-hematopoietic cells during DIO and suggests that targeting immune CB1 receptors provides a new pathway to ameliorate obesity and related metabolic disorders.”

Peripheral CB1 receptor blockade acts as a memory enhancer through a noradrenergic mechanism


“Peripheral inputs continuously shape brain function and can influence memory acquisition, but the underlying mechanisms have not been fully understood. Cannabinoid type-1 receptor (CB1R) is a well-recognized player in memory performance, and its systemic modulation significantly influences memory function. By assessing low arousal/non-emotional recognition memory in mice, we found a relevant role of peripheral CB1R in memory persistence. Indeed, the peripherally-restricted CB1R specific antagonist AM6545 showed significant mnemonic effects that were occluded in adrenalectomized mice, and after peripheral adrenergic blockade. AM6545 also transiently impaired contextual fear memory extinction. Vagus nerve chemogenetic inhibition reduced AM6545-induced mnemonic effect. Genetic CB1R deletion in dopamine β-hydroxylase-expressing cells enhanced recognition memory persistence. These observations support a role of peripheral CB1R modulating adrenergic tone relevant for cognition. Furthermore, AM6545 acutely improved brain connectivity and enhanced extracellular hippocampal norepinephrine. In agreement, intra-hippocampal β-adrenergic blockade prevented AM6545 mnemonic effects. Altogether, we disclose a novel CB1R-dependent peripheral mechanism with implications relevant for lengthening the duration of non-emotional memory.”

Endocannabinoid System and the Otolaryngologist

Otolaryngologic Clinics of North America

“The endocannabinoid system is located throughout the central and peripheral nervous systems, endocrine system, gastrointestinal system, and within inflammatory cells. The use of medical cannabinoids has been gaining traction as a viable treatment option for varying illnesses in recent years. Research is ongoing looking at the effect of cannabinoids for treatment of common otolaryngologic pathologies. This article identifies common otolaryngologic pathologies where cannabinoids may have benefit, discusses potential drawbacks to cannabinoid use, and suggests future directions for research in the application of medical cannabinoids.”

Phytocannabinoids regulate inflammation in IL-1β-stimulated human gingival fibroblasts

Journal of Periodontal Research

“Objectives: Billions of individuals worldwide suffer from periodontal disease, an inflammatory disease that results in hard-tissue and soft-tissue destruction. A viable therapeutic option to treat periodontal disease may be via cannabinoids that exert immunomodulatory effects, and the endocannabinoid system (ECS) is readily present in periodontal tissues that exhibit cannabinoid type 1 and 2 receptors (CB1R and CB2R). Phytocannabinoids (pCBs), which are a part of a heterogeneous group of molecules acting on cannabinoid receptors (CBR) derived from the cannabis plants, have been attributed to a wide variety of effects including anti-inflammatory activity and some pro-inflammatory effects depending on the cell type. Thus, this study aims to examine the effects of pCBs on primary human gingival fibroblasts (HGFs) in IL-1β stimulated (simulated periodontal disease) HGFs.

Results: Cannabidivarin (CBVN or CBDV) (EC50 = 12 nM) and cannabigerol (CBG) (EC50 = 30 nM) exhibited agonist activity on CB2R with intermediate efficacy. Cannabidiol (CBD) did not exhibit activation of the CB2R, and the CB1R activation was not observed with any of the pCBs. Cytotoxicity results showed that concentrations of 2.50 μg/ml or greater for the pCBs were toxic except for CBVN. Lower concentrations of CBD and CBG (0.1-0.75 μg/ml), and CBVN at 2.50 μg/ml exhibited significant effects on HGF proliferation. In IL-1β-stimulated HGFs, prostaglandin E2 (PGE2) production was significantly suppressed only by CBG and CBVN. CBD and CBG treatment alone did, however, elevate PGE2 production significantly compared to control. IL-1β stimulation resulted in a robust increase in the production of all cytokines tested. Treatment of IL-β-stimulated HGF with the three pCBs (1 μg/ml) significantly reduced INF-ɣ, TNF-α, and IL-2. The significant suppression of IL-4 was seen with CBD and CBVN, while only CBVN exerted suppression of IL-13. The three pCBs significantly increased IL-6, IL-10, and IL-12 levels, while none of the pCBs reduced the expression of IL-8 in IL-1β-stimulated HGF.

Conclusion: The effective inhibition of IL-1β-stimulated production of PGE2 and cytokines by the pCB in HGFs suggests that targeting the endocannabinoid system may lead to the development of therapeutic strategies for periodontal therapy. However, each pCB has its unique anti-inflammatory profile, in which certain pro-inflammatory activities are also exhibited. The pCBs alone or in combination may benefit and aid in improving public oral health.”

Cannabidiol impairs fear memory reconsolidation in female rats through dorsal hippocampus CB1 but not CB2 receptor interaction

European Neuropsychopharmacology

“Women present increased susceptibility to anxiety- and stress-related disorders compared to men. A potentially promising pharmacological-based strategy to regulate abnormal aversive memories disrupts their reconsolidation stage after reactivation and destabilization.

Male rodent findings indicate that cannabidiol (CBD), a relatively safe and effective treatment for several mental health conditions, can impair the reconsolidation of aversive memories. However, whether and how CBD influences it in females is still unknown.

The present study addressed this question in contextually fear-conditioned female rats.

We report that systemically administered CBD impaired their reconsolidation, reducing freezing expression for over a week. This action was restricted to a time when the reconsolidation presumably lasted (< six hours post-retrieval) and depended on memory reactivation/destabilization. Moreover, the impairing effects of CBD on memory reconsolidation relied on the activation of cannabinoid type-1 but not type-2 receptors located in the CA1 subregion of the dorsal hippocampus.

CBD applied directly to this brain area was sufficient to reproduce the effects of systemic CBD treatment. Contextual fear memories attenuated by CBD did not show reinstatement, an extinction-related feature. By demonstrating that destabilized fear memories are sensitive to CBD and how it hinders mechanisms in the DH CA1 that may restabilize them in female rats, the present findings concur that reconsolidation blockers are viable and could be effective in disrupting abnormally persistent and distressing aversive memories such as those related to posttraumatic stress disorder.”

Cross-talk between neurosteroid and endocannabinoid systems in cannabis addiction

“Steroids and endocannabinoids are part of two modulatory systems and some evidence has shown their interconnections in several functions.

Homeostasis is a common steady-state described in the body, which is settled by regulatory systems to counterbalance deregulated or allostatic set points towards an equilibrium. This regulation is of primary significance in the central nervous system for maintaining neuronal plasticity and preventing brain-related disorders.

In this context, the recent discovery of the shutdown of the endocannabinoid system (ECS) overload by the neurosteroid pregnenolone has highlighted new endogenous mechanisms of ECS regulation related to cannabis-induced intoxication.

These mechanisms involve a regulatory loop mediated by overactivation of the central type-1 cannabinoid receptor (CB1R), which triggers the production of its own regulator, pregnenolone. Therefore, this highlights a new process of regulation of steroidogenesis in the brain.

Pregnenolone, long considered an inactive precursor of neurosteroids, can then act as an endogenous negative allosteric modulator of CB1R. The present review aims to shed light on a new framework for the role of ECS in the addictive characteristics of cannabis with the novel endogenous mechanism of ECS involving the neurosteroid pregnenolone.

In addition, this new endogenous regulatory loop could provide a relevant therapeutic model in the current context of increasing recreational and medical use of cannabis.”

“Pregnenolone blocks cannabinoid-induced acute psychotic-like states in mice”

“Pregnenolone Can Protect the Brain from Cannabis Intoxication”

Cannabinoids receptors in Covid-19: Perpetrators and victims

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“COVID-19 is caused by SARS-CoV-2 and leads to acute lung injury (ALI), acute respiratory distress syndrome (ARDS), and extrapulmonary manifestations in severely affected cases. However, most of the affected cases are mild or asymptomatic.

Cannabinoids (CBs) such as tetrahydrocannabinol (THC) and cannabidiol (CBD), which act on G-protein-coupled receptors called CB1 and CB2, have anti-inflammatory effects. Many published studies show that CBs are effective in various inflammatory disorders, viral infections, and attenuation of ALI and ARDS.

Therefore, the aim of the present narrative review was to summarize the possible immunological role of CBs in COVID-19. The effects of CBs are controversial, although they have beneficial effects via CB2 receptors and adverse effects via CB1 receptors against ALI, ARDS, and hyperinflammation, which are hallmarks of COVID-19.

The present narrative review has shown that CBs effectively manage ALI and ARDS by suppressing pro-inflammatory cytokines, which are common in COVID-19. Therefore, CBs may be used to manage COVID-19 because of their potent anti-inflammatory effects with suppression of pro-inflammatory cytokines and inhibition of inflammatory signaling pathways.”