Exogenous Cannabinoids Research Articles

Serotonin 2A receptors and cannabinoids.

Accumulating evidence has proven that both exogenous cannabinoids as well as imbalances in the endocannabinoid system are involved in the onset and development of mental disorders such as anxiety, depression, or schizophrenia. Extensive recent research in this topic has mainly focused on the molecular mechanisms by which cannabinoid agonists may contribute to the pathophysiology of these disorders. Initially, serotonin neurotransmitter garnered most attention due to its relationship to mood disorders and mental diseases, with little attention to specific receptors. To date, the focus has redirected toward the understanding of different serotonin receptors, through a demonstration of its versatile pharmacology and synergy with different modulators. Serotonin 2A receptors are a good example of this phenomenon, and the complex signaling that they trigger appears of high relevance in the context of mental disorders, especially in schizophrenia. This chapter will analyze most relevant attributes of serotonin 2A receptors and the endocannabinoid system, and will highlight the evidence toward the functional bidirectional interaction between these elements in the brain as well as the impact of the endocannabinoid system dysregulation on serotonin 2A receptors functionality.

The Immune Endocannabinoid System of the Tumor Microenvironment.

Leukocytes are part of the tumor microenvironment (TME) and are critical determinants of tumor progression. Because of the immunoregulatory properties of cannabinoids, the endocannabinoid system (ECS) may have an important role in shaping the TME. Members of the ECS, an entity that consists of cannabinoid receptors, endocannabinoids and their synthesizing/degrading enzymes, have been associated with both tumor growth and rejection. Immune cells express cannabinoid receptors and produce endocannabinoids, thereby forming an “immune endocannabinoid system”. Although in vitro effects of exogenous cannabinoids on immune cells are well described, the role of the ECS in the TME, and hence in tumor development and immunotherapy, is still elusive. This review/opinion discusses the possibility that the “immune endocannabinoid system” can fundamentally influence tumor progression. The widespread influence of cannabinoids on immune cell functions makes the members of the ECS an interesting target that could support immunotherapy.

The Interplay between Cancer Biology and the Endocannabinoid System-Significance for Cancer Risk, Prognosis and Response to Treatment.

Simple SummaryThis review analyses the complex involvement of the various components of the endocannabinoid system (ECS) in the susceptibility to cancer, prognosis, and response to treatment, focusing on its relationship with cancer biology in selected solid cancers (breast, gastrointestinal, gynaecological, prostate cancer, thoracic, thyroid, central nervous system (CNS) tumours, and melanoma). The same ECS component can exert both protective and pathogenic effects in different tumour subtypes, which are often pathologically driven by different biological factors. Although an attractive target in cancer, the use of components in anti-cancer treatment is still interlinked with many legal and ethical issues that need to be considered. The legislation which outlines the permissive boundaries of their therapeutic use in oncology is still unable to follow the current scientific burden of evidence, but the number of ongoing clinical trials might tip the scale forward in the near future.The various components of the endocannabinoid system (ECS), such as the cannabinoid receptors (CBRs), cannabinoid ligands, and the signalling network behind it, are implicated in several tumour-related states, both as favourable and unfavourable factors. This review analyses the ECS’s complex involvement in the susceptibility to cancer, prognosis, and response to treatment, focusing on its relationship with cancer biology in selected solid cancers (breast, gastrointestinal, gynaecological, prostate cancer, thoracic, thyroid, CNS tumours, and melanoma). Changes in the expression and activation of CBRs, as well as their ability to form distinct functional heteromers affect the cell’s tumourigenic potential and their signalling properties, leading to pharmacologically different outcomes. Thus, the same ECS component can exert both protective and pathogenic effects in different tumour subtypes, which are often pathologically driven by different biological factors. The use of endogenous and exogenous cannabinoids as anti-cancer agents, and the range of effects they might induce (cell death, regulation of angiogenesis, and invasion or anticancer immunity), depend in great deal on the tumour type and the specific ECS component that they target. Although an attractive target, the use of ECS components in anti-cancer treatment is still interlinked with many legal and ethical issues that need to be considered.

The CB1 Receptor Differentially Regulates IFN-γ Production In Vitro and in Experimental Autoimmune Encephalomyelitis.

Introduction: Activation of the peripheral immune system and the infiltration of immune cells into the central nervous system are both key features of the experimental autoimmune encephalomyelitis (EAE) model. By exploring how the endocannabinoid system works to modulate this response, we can better understand how exogenous cannabinoids, such as THC, might be used to modulate the immune responses of multiple sclerosis patients. Materials and Methods: In this study, we examined the role of the CB1 receptor in IFN-γ and IL-17A production in the EAE model and in vitro stimulations of naive splenocytes using Cnr1-/- mice and wild-type (WT) littermates. We also introduce a novel method of scoring spinal cord histological sections to show the differences in disease severity between Cnr1-/- and WT mice with EAE. Results: Clinical scores of Cnr1-/-/EAE and WT/EAE mice showed more severe disease progression in Cnr1-/- mice, which was confirmed using our new histological scoring method. In the peripheral immune system, IFN-γ production by restimulated splenocytes from Cnr1-/-/EAE mice, compared with WT/EAE mice, was increased and the primary source of IFN-γ was a CD3- cell population; however, IFN-γ production by Cnr1-/- splenocytes was decreased compared with WT splenocytes when the primary source of IFN-γ was CD3+ T cells in cultures from naive mice stimulated by either anti-CD3/anti-CD28 antibodies or Staphylococcal superantigens. Conclusion: These findings suggest a duality to the CB1 receptor's effects on the peripheral immune response, which varies based on the specific cell types stimulated. Knowledge of the complex nature of a receptor is an important part of determining its potential usefulness as a therapeutic target, and these findings further define the role of CB1 in IFN-γ responses.

Epigenetics and the endocannabinoid system signaling: An intricate interplay modulating neurodevelopment

The endocannabinoid (eCB) system is a complex system comprising endogenous cannabinoids (eCBs), their synthesis and degradation enzymes, and cannabinoid receptors. These elements crucially regulate several biological processes during neurodevelopment, such as proliferation, differentiation, and migration. Recently, eCBs were also reported to have an epigenetic action on genes that play key functions in the neurotransmitter signaling, consequently regulating their expression. In turn, epigenetic modifications (e.g. DNA methylation, histone modifications) may also modulate the function of eCB system’s elements. For example, the expression of the cnr gene in the central nervous system may be epigenetically regulated (e.g. DNA methylation, histone modifications), thus altering the function of the cannabinoid receptor type-1 (CB1R). Considering the importance of the eCB system during neurodevelopment, it is thus reasonable to expect that alterations in this interaction between the eCB system and epigenetic modifications may give rise to neurodevelopmental disorders.Here, we review key concepts related to the regulation of neuronal function by the eCB system and the different types of epigenetic modifications. In particular, we focus on the mechanisms involved in the intricate interplay between both signaling systems and how they control cell fate during neurodevelopment. Noteworthy, such mechanistic understanding assumes high relevance considering the implications of the dysregulation of key neurogenic processes towards the onset of neurodevelopment-related disorders.Moreover, considering the increasing popularity of cannabis and its synthetic derivatives among young adults, it becomes of utmost importance to understand how exogenous cannabinoids may epigenetically impact neurodevelopment.

Abstract 4035: Cannabidiol inhibits the long-term survival of a variety of cancers

Abstract Cannabis has resurfaced as a natural alternative or adjunctive treatment for a variety of chronic conditions, such as anorexia in patients with the AIDS wasting syndrome and chemotherapy-related nausea and vomiting. Exogenous cannabinoids, such as Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD), are found in the cannabis sativa plant. CBD has been shown to have anti-proliferative and pro-apoptotic effects in addition to preventing invasion and metastasis of various cancer cells. Such effects of CBD have been shown in certain cell lines of breast cancer, leukemia, glioma, small cell lung cancer, and colorectal cancer. Currently, the mechanism by which CBD exerts its effects are not fully understood. Here we have investigated CBD's effects on the long-term viability and mechanisms of cell death in a variety of cancer cell lines. Cancer cell lines of osteosarcoma (U2-OS), adenocarcinoma of the cervix (HeLa 1.2.11), metastatic breast cancer (MDA-MB 231), large cell lung carcinoma (H460) and malignant melanoma (A375) were plated on 12-well plates. 100% pure CBD isolated from cannabis sativa (generously provided by America's Finest CBD) was dissolved in ethanol and added directly to growth medium at various concentrations to determine the optimal dose in which the cells could no longer maintain viability. After 7-10 days, cells were stained with crystal violet. The blue dye was later extracted, quantified with a spectrometer, and dose response curves were plotted. For PARP cleavage analysis, cells were exposed to a certain concertation of CBD concentration and collected over 24-hour intervals. In addition, we have also performed RNA sequencing (RNA Seq) analysis using the melanoma cell line, A375, in an attempt to uncover the molecular mechanism of cell death induced by CBD treatment. Our long-term viability analysis demonstrate that a dose dependent response was present for each cell line exposed to CBD. We showed that CBD allows for a dose dependent killing in a variety of cancer cell lines, including large cell lung carcinoma, metastatic breast cancer, malignant melanoma, cervical carcinoma and osteosarcoma. IC50 of each cell line was determined as follows: A375 - 2.45μM, H460 - 8.47 μM, MDA-MB-231 - 8.35 μM, HeLa1.2.11 - 4.1 μM, and U2OS - 4.63 μM. The more aggressive cancer cell lines H460 and MDA-MB-231 required relatively higher dosages of CBD to kill the cells. A375, a malignant melanoma cell line, is the most sensitive cancer cell line to CBD tested so far. Apoptosis as a mechanism of cell death was confirmed with the presence of PARP cleavage in A375, H460, and MDA-MB-231 cell lines. Preliminary RNA Sequencing results suggest that heightened endoplasmic reticulum (ER) stress response in CBD treated cells is likely the cause of cell death. In summary, CBD demonstrates dose-dependent killing effects on a wide range of cancer cell lines, many of which have demonstrated a mechanism through apoptosis. Intriguingly, one of the melanoma cell lines is the most sensitive cancer cell line tested so far. Our RNA Sequencing analysis showed that CBD treatment induces a drastic increase of ER stress response, suggesting a potential mechanism of CBD induced apoptosis in cancers. In the future, we plan to develop a CBD cream and test its efficacy on preventing and/or treating skin cancers. Citation Format: Emily Seltzer, Andrea Watters, Dong Zhang. Cannabidiol inhibits the long-term survival of a variety of cancers [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4035.

Developmentally Transient CB1Rs on Cerebellar Afferents Suppress Afferent Input, Downstream Synaptic Excitation, and Signaling to Migrating Neurons.

The endocannabinoid system plays important roles in brain development, but mechanistic studies have focused on neuronal differentiation, migration, and synaptogenesis, with less attention to transcellular interactions that coordinate neurodevelopmental processes across developing neural networks. We determined that, in the developing rodent cerebellar cortex (of both sexes), there is a transient window when the dominant brain cannabinoid receptor, CB1R, is expressed on afferent terminals instead of output neuron Purkinje cell synapses that dominate the adult cerebellum. Activation of these afferent CB1Rs suppresses synaptic transmission onto developing granule cells, and consequently also suppresses excitation of downstream neurons in the developing cortical network, including nonsynaptic, migrating neurons. Application of a CB1R antagonist during afferent stimulation trains and depolarizing voltage steps caused a significant, sustained potentiation of synaptic amplitude. Our data demonstrate that transiently expressed afferent CB1Rs regulate afferent synaptic strength during synaptogenesis, which enables coordinated dampening of transcortical developmental signals.SIGNIFICANCE STATEMENT The endogenous cannabinoid system plays diverse roles in brain development, which, combined with the rapidly changing legal and medical status of cannabis-related compounds, makes understanding how exogenous cannabinoids affect brain development an important biomedical objective. The cerebellum is a key brain region in a variety of neurodevelopmental disorders, and the adult cerebellum has one of the highest expression levels of CB1R, but little is known about CB1R in the developing cerebellum. Here we report a developmentally distinct expression and function of CB1R in the cerebellum, in which endogenous or exogenous activation of CB1Rs modifies afferent synaptic strength and coordinated downstream network signaling. These findings have implications for recreational and medical use of exogenous cannabinoids by pregnant and breastfeeding women.

Age-dependent hormesis-like effects of the synthetic cannabinoid CP55940 in C57BL/6 mice

Use of cannabis and cannabinoid-containing substances is increasing among geriatric patients, despite relatively sparse preclinical evidence in aged models. To better understand the effects of exogenous cannabinoids on aging male and female rodents, we compared the age- and dose-dependent physiological and behavioral effects of the synthetic cannabinoid CP55940 in young–adult and aged C57BL/6 mice. Locomotion, body temperature, thermal nociception, and fecal output were measured following CP55940 administration. Our findings indicate that CP55940 is more potent and efficacious in older mice, evidenced by exaggerated antinociception and locomotor inhibition when compared to younger adult mice. In addition, we report that low doses of CP55940 paradoxically stimulate locomotion in young–adult (4 m) mice; however, this hormesis-like response is not as evident in aged animals (21–24 m). These bidirectional effects appear to be mediated via the endocannabinoid CB1 and CB2 receptors.

Cannabidiol attenuates methamphetamine-induced conditioned place preference via the Sigma1R/AKT/GSK-3β/CREB signaling pathway in rats.

Methamphetamine (METH) is a highly addictive psychostimulant. Cannabidiol (CBD) is an exogenous cannabinoid without psychostimulating activity, which has potential therapeutic effects on opioid addiction. However, it is unclear whether CBD has therapeutic effects on METH-induced motivational effects. The present study examines whether CBD has a protective effect on METH-induced conditioned place preference (CPP) in rats by regulating the Sigma1R and AKT-GSK3β-CREB signaling pathway. Seventy rats were equally and randomly divided into seven groups. The rat CPP model was established via the intraperitoneal injection (IP) of 2mg/kg of METH. Next, the intraperitoneal injection of 10, 20, 40, and 80mg/kg CBD was performed 1h prior to the injection of saline or METH. The protein expression levels of Sigma1R, AKT, p-AKT, GSK-3β, p-GSK-3β, CREB, and p-CREB in the rats' prefrontal cortex, nucleus accumbens, and hippocampus and ventral tegmental were detected using western blot analysis. CBD was found to inhibit METH-induced CPP in a dose-dependent fashion. The expression levels of Sigma1R, p-AKT, p-GSK3β, and p-CREB increased significantly in the METH-induced CPP model. Treatment involving different doses of CBD caused differential inhibitory responses in the cellular protein abundance of Sigma1R, p-AKT, p-GSK3β, and p-CREB across various brain regions. The present study found that METH can induce CPP in rats. When a pretreatment of CBD is applied, the CBD can weaken CPP in METH-induced rats by regulating the SigmaR1/AKT/GSK-3β/CREB signaling pathway. The results of this study indicate that CBD has a potential therapeutic effect on METH-induced rewarding effects.

HIV Tat Protein Selectively Impairs CB1 Receptor-Mediated Presynaptic Inhibition at Excitatory But Not Inhibitory Synapses.

Despite the success of antiretroviral therapy in suppressing viral load, nearly half of the 37 million people infected with HIV experience cognitive and motor impairments, collectively classified as HIV-associated neurocognitive disorders (HAND). In the CNS, HIV-infected microglia release neurotoxic agents that act indirectly to elicit excitotoxic synaptic injury. HIV trans-activator of transcription (Tat) protein is one such neurotoxin that is thought to play a major role in the neuropathogenesis of HAND. The endocannabinoid (eCB) system provides on-demand neuroprotection against excitotoxicity, and exogenous cannabinoids attenuate neurotoxicity in animal models of HAND. Whether this neuroprotective system is altered in the presence of HIV is unknown. Here, we examined the effects of Tat on the eCB system in rat primary hippocampal cultures. Using whole-cell patch-clamp electrophysiology, we measured changes in retrograde eCB signaling following exposure to Tat. Treatment with Tat significantly reduced the magnitude of depolarization-induced suppression of excitation (DSE) in a graded manner over the course of 48 h. Interestingly, Tat did not alter this form of short-term synaptic plasticity at inhibitory terminals. The Tat-induced decrease in eCB signaling resulted from impaired CB1 receptor (CB1R)-mediated presynaptic inhibition of glutamate release. This novel loss-of-function was particularly dramatic for low-efficacy agonists such as the eCB 2-arachidonoylglycerol (2-AG) and Δ9-tetrahydrocannabinol (Δ9-THC), the main psychoactive ingredient in marijuana. Our observation that HIV Tat decreases CB1R function in vitro suggests that eCB-mediated neuroprotection may be reduced in vivo; this effect of Tat may contribute to synaptodendritic injury in HAND.

Impairment of Synaptic Plasticity by Cannabis, Δ9-THC, and Synthetic Cannabinoids.

The ability of neurons to dynamically and flexibly encode synaptic inputs via short- and long-term plasticity is critical to an organism's ability to learn and adapt to the environment. Whereas synaptic plasticity may be encoded by pre- or postsynaptic mechanisms, current evidence suggests that optimization of learning requires both forms of plasticity. Endogenous cannabinoids (eCBs) play critical roles in modulating synaptic transmission via activation of cannabinoid CB1 receptors (CB1Rs) in many central nervous system (CNS) regions, and the eCB system has been implicated, either directly or indirectly, in several forms of synaptic plasticity. Because of this, perturbations within the eCB signaling system can lead to impairments in a variety of learned behaviors. One agent of altered eCB signaling is exposure to "exogenous cannabinoids" such as the primary psychoactive constituent of cannabis, Δ9-THC, or illicit synthetic cannabinoids that in many cases have higher potency and efficacy than Δ9-THC. Thus, by targeting the eCB system, these agonists can produce widespread impairment of synaptic plasticity by disrupting ongoing eCB function. Here, we review studies in which Δ9-THC and synthetic cannabinoids impair synaptic plasticity in a variety of neuronal circuits and examine evidence that this contributes to their well-documented ability to disrupt cognition and behavior.

Differential effects of opioid versus alcohol dependence on pain avoidance behavior and regional endocannabinoid system deficiency

In contrast to their analgesic effects, chronic use of opioids or alcohol often creates the paradoxical emergence of heightened pain sensitivity, termed hyperalgesia, during withdrawal. A hallmark symptom of hyperalgesia is the development of motivational strategies to avoid painful stimuli, and we have shown that adult male Wistar rats display pain avoidance behavior using the mechanical conflict avoidance system when in withdrawal from morphine (n=10–11/group) and alcohol (n=8–9/group). The present study seeks to identify how morphine and alcohol differentially affect pain avoidance behavior and endocannabinoid signaling within pain‐ and avoidance‐ associated brain regions, including the periaqueductal grey (PAG) and basolateral amygdala (BLA).Morphine dependence was induced via daily subcutaneous morphine injections (escalating dose of 10–20mg/kg) over 3 weeks. Alcohol dependence was induced via exposure to chronic intermittent ethanol vapor (CIEV) for 14 hours per day for 8 weeks. Pain avoidance behavior was quantified using the MCS as the latency for rats to exit a brightly lit start chamber onto nociceptive probes of varying heights (0–5mm) to enter a dark goal box. Western blotting was conducted for quantification of endocannabinoid system‐related proteins cannabinoid receptor 1 (CB1R) and eCB synthetic and catabolic enzymes diacylglycerol lipase alpha (DAGLa), monoacylglycerol lipase (MAGL).We found that morphine and alcohol dependence produced distinct patterns of pain avoidance behavior, where morphine dependence produced a hyperalgesic behavior and ethanol dependence produced an allodynic phenotype. This behavior negatively correlated with PAG levels of CB1R and DAGLa in morphine dependent animals and with the ratio of BLA DAGLa:MAGL in alcohol dependent animals, reflective of a decreased eCB tone in these animals. This suggests that exogenous cannabinoid treatment may be an effective therapy for substance‐induced hyperalgesia. Because substance‐induced hyperalgesia and negative affective components of pain are integral to addiction reinforcement, targeting these behaviors therapeutically could treat substance abuse.Support or Funding InformationNIAAA: T32AA007577, R00AA020839, R01AA025996, R21AA025736, NIH‐NICHD‐2018‐05

Toxicological properties of Δ9-tetrahydrocannabinol and cannabidiol.

Cannabis sativa L. contains more than 100 phytocannabinoids that can interact with cannabinoid receptors CB1 and CB2. None of the cannabinoid receptor ligands is entirely CB1- or CB2-specific. The effects of cannabinoids therefore differ not just because of different potency at cannabinoid receptors but also because they can interact with other non-CB1 and non-CB2 targets, such as TRPV1, GPR55, and GPR119. The most studied phytocannabinoid is Δ9-tetrahydrocannabinol (THC). THC is a partial agonist at both cannabinoid receptors, but its psychotomimetic effect is produced primarily via activation of the CB1 receptor, which is strongly expressed in the central nervous system, with the noteworthy exception of the brain stem. Although acute cognitive and other effects of THC are well known, the risk of irreversible neuropsychological effects of THC needs further research to elucidate the association. Unlike THC, phytocannabinoid cannabidiol (CBD) does not appear to have psychotomimetic effects but may interact with some of the effects of THC if taken concomitantly. CBD administered orally has recently undergone well-controlled clinical trials to assess its safety in the treatment of paediatric epilepsy syndromes. Their findings point to increased transaminase levels as a safety issue that calls for postmarketing surveillance for liver toxicity. The aim of this review is to summarise what is known about acute and chronic toxicological effects of both compounds and address the gaps in knowledge about the safety of exogenous cannabinoids that are still open.

The "Entourage Effect": Terpenes Coupled with Cannabinoids for the Treatment of Mood Disorders and Anxiety Disorders.

Mood disorders are the most prevalent mental conditions encountered in psychiatric practice. Numerous patients suffering from mood disorders present with treatment-resistant forms of depression, co-morbid anxiety, other psychiatric disorders and bipolar disorders. Standardized essential oils (such as that of Lavender officinalis) have been shown to exert clinical efficacy in treating anxiety disorders. As endocannabinoids are suggested to play an important role in major depression, generalized anxiety and bipolar disorders, Cannabis sativa was suggested for their treatment. The endocannabinoid system is widely distributed throughout the body including the brain, modulating many functions. It is involved in mood and related disorders, and its activity may be modified by exogenous cannabinoids. CB1 and CB2 receptors primarily serve as the binding sites for endocannabinoids as well as for phytocannabinoids, produced by cannabis inflorescences. However, ‘cannabis’ is not a single compound product but is known for its complicated molecular profile, producing a plethora of phytocannabinoids alongside a vast array of terpenes. Thus, the “entourage effect” is the suggested positive contribution derived from the addition of terpenes to cannabinoids. Here, we review the literature on the effects of cannabinoids and discuss the possibility of enhancing cannabinoid activity on psychiatric symptoms by the addition of terpenes and terpenoids. Possible underlying mechanisms for the anti-depressant and anxiolytic effects are reviewed. These natural products may be an important potential source for new medications for the treatment of mood and anxiety disorders.

Δ9-tetrahydrocannabinol and 2-AG decreases neurite outgrowth and differentially affects ERK1/2 and Akt signaling in hiPSC-derived cortical neurons

Endocannabinoids regulate different aspects of neurodevelopment. In utero exposure to the exogenous psychoactive cannabinoid Δ9-tetrahydrocannabinol (Δ9-THC), has been linked with abnormal cortical development in animal models. However, much less is known about the actions of endocannabinoids in human neurons. Here we investigated the effect of the endocannabinoid 2-arachidonoyl glycerol (2AG) and Δ9-THC on the development of neuronal morphology and activation of signaling kinases, in cortical neurons derived from human induced pluripotent stem cells (hiPSCs). Our data indicate that the cannabinoid type 1 receptor (CB1R), but not the cannabinoid 2 receptor (CB2R), GPR55 or TRPV1 receptors, is expressed in young, immature hiPSC-derived cortical neurons. Consistent with previous reports, 2AG and Δ9-THC negatively regulated neurite outgrowth. Interestingly, acute exposure to both 2AG and Δ9-THC inhibited phosphorylation of serine/threonine kinase extracellular signal-regulated protein kinases (ERK1/2), whereas Δ9-THC also reduced phosphorylation of Akt (aka PKB). Moreover, the CB1R inverse agonist SR 141716A attenuated the decrease in neurite outgrowth and ERK1/2 phosphorylation induced by 2AG and Δ9-THC. Taken together, our data suggest that hiPSC-derived cortical neurons express CB1Rs and are responsive to exogenous cannabinoids. Thus, hiPSC-neurons may represent a good cellular model for investigating the role of the endocannabinoid system in regulating cellular processes in developing human neurons.

Role of Nitric Oxide in the Antipruritic Effect of WIN 55,212-2, a Cannabinoid Agonist.

Introduction:For centuries, cannabinoids are known to be effective in pain relief. Itch is an unpleasant sensation that provokes a desire to scratch. Since itch and pain are two sensations sharing a lot in common, we aimed to investigate whether the cannabinoid agonist WIN 55,212-2 reduces serotonin-induced scratching behavior and also observe whether modulation of Nitric Oxide (NO) production mediates the antipruritic effect of WIN 55,212-2.Methods:Scratching behavior is induced by intradermal injection of serotonin (50 μg/50 μL/mouse) to BALB/c mice. The cannabinoid agonist WIN 55,212-2 (1, 3, 10 mg/kg, IP) was given 30 min before serotonin injection. To observe the effect of NO modulation on the antipruritic effect of cannabinoids, the endothelial nitric oxide synthase (NOS) inhibitor L-NAME (3 mg/kg, IP), the neuronal NOS inhibitor 7-nitroindazole (3 mg/kg, IP), and the NO precursor L-arginine (100 mg/kg, IP) were administered together with WIN 55,212-2.Results:WIN 55,212-2 reduced serotonin-induced scratches at higher doses (3, 10 mg/ kg; P<0.0001). The endothelial NOS inhibitor L-NAME, the neuronal NOS inhibitor 7-nitroindazole, and the nitric oxide precursor L-arginine did not influence the antipruritic action of WIN 55,212-2. When NO modulators were used alone, only the neuronal NOS inhibitor 7-nitroindazole attenuated serotonin-induced scratches (P<0.0001).Conclusion:Our findings indicate that exogenous cannabinoids may attenuate serotonininduced scratches and NO does not mediate the antipruritic effect of WIN 55,212-2. On the other hand, neuronal NOS inhibition may play a role in the production of serotonin-induced scratches.

Cannabinoids: A Guide for Use in the World of Gastrointestinal Disease.

Cannabinoids have been known as the primary component of cannabis for decades, but the characterization of the endocannabinoid system (ECS) in the 1990s opened the doors for cannabis' use in modern medicine. The 2 main receptors of this system, cannabinoid receptors 1 and 2, are found on cells of various tissues, with significant expression in the gastrointestinal (GI) tract. The characterization of the ECS also heralded the understanding of endocannabinoids, naturally occurring compounds synthesized in the human body. Via secondary signaling pathways acting on vagal nerves, nociceptors, and immune cells, cannabinoids have been shown to have both palliative and detrimental effects on the pathophysiology of GI disorders. Although research on the effects of both endogenous and exogenous cannabinoids has been slow due to the complicated legal history of cannabis, discoveries of cannabinoids' treatment potential have been found in various fields of medicine, including the GI world. Medical cannabis has since been offered as a treatment for a myriad of conditions and malignancies, including cancer, human immunodeficiency virus/acquired immunodeficiency syndrome, multiple sclerosis, chronic pain, nausea, posttraumatic stress disorder, amyotrophic lateral sclerosis, cachexia, glaucoma, and epilepsy. This article hopes to create an overview of current research on cannabinoids and the ECS, detail the potential advantages and pitfalls of their use in GI diseases, and explore possible future developments in this field.

Psychosocial and Biological Aspects of Synthetic and Natural FAAH Inhibitors

Molecular engineers are studying FAAH as a target for pharmaceuticals as controlling levels of FAAH may produce some of the same health effects that excite clinicians about the potential for phytocannabinoid-based medicines. Synthetic cannabinoids work by flooding the system with molecules structurally similar to THC and other phytocannabinoids. Medicines that inhibit the body’s production of FAAH are theorized to have a similar effect by maximizing the concentration of deficient endocannabinoids in the nervous system. Technological limitations coupled with a suppression of research of biologic cannabinoids at many major research universities have limited our understanding of the endocannabinoid system. Questions still need to be answered to provide a comprehensive comparison of biologic with synthetic FAAH inhibitors. Advancement and research aimed at understanding of endogenous and exogenous cannabinoids, and particularly the medicinal properties of the Trans-Δ⁹-Tetrahydrocannabinol (THC) molecule and its endocannabinoid equivalent anandamide are hindered by prohibitive restrictions resulting from the Food and Drug Administration (FDA), Drug Enforcement Administration (DEA), National Institute of Health (NIH), and the National Institute on Drug Abuse (NIDA). The mission statements of each of these entities effectively integrate to ensure research and utilization of the medicinal properties of THC will be nearly impossible to attain.

Зміни активності ангіотензинперетворюючого ферменту в структурах гіпоталамо-гіпофізарно-адренокортикальної системи та функції кори надниркових залоз щурів під дією метанандаміду

Мета роботи — дослідити вплив метанандаміду — метаболічно стійкого похідного ендоканабіноїду N-арахідоноїлетаноламіну на активність ангіотензинперетворюючого ферменту (АПФ) у центрах регуляції гіпоталамо-гіпофізарно-адренокортикальної системи (ГГАС), а також на рівень кортикостероїдів у плазмі крові щурів. Матеріал і методи. Активність АПФ у гіпоталамусі, аденогіпофізі, надниркових залозах і плазмі крові щурів визначали за допомогою флуориметричного методу, використовуючи як субстрат Benzoyl-Gly-His-Leu (Sigma, США). Вміст 11-гідроксикортикостероїдів (11-ОКС) у плазмі крові щурів встановлювали із застосуванням флуориметричного мікрометоду. Результати. Через 1 годину після одноразового введення інтактним щурам метанандаміду в дозах 0,2 мг/кг і 0,02 мг/кг активність АПФ у центральних ланках ГГАС — гіпоталамусі та аденогіпофізі підвищувалася, активність АПФ унадниркових залозах та активність циркулюючого в крові ферменту знижувалися. Після одноразового введення інтактним щурам метанандаміду в дозі 0,2 мг/кг виявлено підвищення рівня 11-ОКС у плазмі крові щурів, введення метанандаміду в низькій дозі — 0,02 мг/кг не призводило до вірогідних змін рівня кортикостероїдів у крові тварин. Висновки. Екзогенні канабіноїди модулюють активність ангіотензинової системи в різних ланках ГГАС, стимулюючи активність АПФ у гіпоталамусі й аденогіпофізі та знижуючи активність ферментув надниркових залозах і плазмі крові через 1 годину після одноразового введення метанандаміду інтактним щурам. Через кортикотропін-рилізинг активність ангіотензинів гіпоталамуса та аденогіпофіза підвищення активності АПФ у цих структурах може бути одним із важливих чинників активації ГГАС, зокрема синтезу кортикостероїдів, спричиненого одноразовим введенням метанандаміду у високих дозах.

Characterisation and localisation of the endocannabinoid system components in the adult human testis

Heavy use of cannabis (marijuana) has been associated with decreased semen quality, which may reflect disruption of the endocannabinoid system (ECS) in the male reproductive tract by exogenous cannabinoids. Components of ECS have been previously described in human spermatozoa and in the rodent testis but there is little information on the ECS expression within the human testis. In this study we characterised the main components of the ECS by immunohistochemistry (IHC) on archived testis tissue samples from 15 patients, and by in silico analysis of existing transcriptome datasets from testicular cell populations. The presence of 2-arachidonoylglycerol (2-AG) in the human testis was confirmed by matrix-assisted laser desorption ionization imaging analysis. Endocannabinoid-synthesising enzymes; diacylglycerol lipase (DAGL) and N-acyl-phosphatidylethanolamine-specific phospholipase D (NAPE-PLD), were detected in germ cells and somatic cells, respectively. The cannabinoid receptors, CNR1 and CNR2 were detected at a low level in post-meiotic germ cells and Leydig- and peritubular cells. Different transcripts encoding distinct receptor isoforms (CB1, CB1A, CB1B and CB2A) were also differentially distributed, mainly in germ cells. The cannabinoid-metabolising enzymes were abundantly present; the α/β-hydrolase domain-containing protein 2 (ABHD2) in all germ cell types, except early spermatocytes, the monoacylglycerol lipase (MGLL) in Sertoli cells, and the fatty acid amide hydrolase (FAAH) in late spermatocytes and post-meiotic germ cells. Our findings are consistent with a direct involvement of the ECS in regulation of human testicular physiology, including spermatogenesis and Leydig cell function. The study provides new evidence supporting observations that recreational cannabis can have possible deleterious effects on human testicular function.