“Exposure to excessive or uncontrolled stress is a major factor associated with various diseases including post-traumatic stress disorder (PTSD). The consequences of exposure to trauma are affected not only by aspects of the event itself, but also by the frequency and severity of trauma reminders. It was suggested that in PTSD, hippocampal-dependent memory is compromised while amygdala-dependent memory is strengthened. Several lines of evidence support the role of the endocannabinoid (eCB) system as a modulator of the stress response. In this study we aimed to examine cannabinoids modulation of the long-term effects (i.e., 1 month) of exposure to a traumatic event on memory and plasticity in the hippocampus and amygdala. Cannabinoids prevent the differential long-term effects of exposure to severe stress on hippocampal- and amygdala-dependent memory and plasticity. Taken together, these findings suggest the involvement of the endocannabinoid system, and specifically CB1 receptors, in the opposite effects of severe stress on memory and plasticity in the hippocampus and amygdala.” https://www.ncbi.nlm.nih.gov/pubmed/28667676 http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002/hipo.22755]]>
Category Archives: Endocannabinoid System
Circulating Endocannabinoids: From Whence Do They Come and Where are They Going?
“The goal of this review is to summarize studies in which concentrations of circulating endocannabinoids in humans have been examined in relationship to physiological measurements and pathological status. The roles of endocannabinoids in the regulation of energy intake and storage have been well studied and the data obtained consistently support the hypothesis that endocannabinoid signaling is associated with increased consumption and storage of energy. Physical exercise mobilizes endocannabinoids, which could contribute to refilling of energy stores and also to the analgesic and mood-elevating effects of exercise. Circulating concentrations of 2-arachidonoylglycerol are very significantly circadian and dysregulated when sleep is disrupted. Other conditions under which circulating endocannabinoids are altered include inflammation and pain. A second important role for endocannabinoid signaling is to restore homeostasis following stress. Circulating endocannabinoids are stress-responsive and there is evidence that their concentrations are altered in disorders associated with excessive stress, including post-traumatic stress disorder. Although determination of circulating endocannabinoids can provide important information about the state of endocannabinoid signaling and thus allow for hypotheses to be defined and tested, the large number of physiological factors that contribute to their circulating concentrations makes it difficult to use them in isolation as a biomarker for a specific disorder.” https://www.ncbi.nlm.nih.gov/pubmed/28653665 https://www.nature.com/npp/journal/vaop/naam/abs/npp2017130a.html]]>
The cannabinoid system and pain.
“Chronic pain states are highly prevalent and yet poorly controlled by currently available analgesics, representing an enormous clinical, societal, and economic burden. Existing pain medications have significant limitations and adverse effects including tolerance, dependence, gastrointestinal dysfunction, cognitive impairment, and a narrow therapeutic window, making the search for novel analgesics ever more important. In this article, we review the role of an important endogenous pain control system, the endocannabinoid (EC) system, in the sensory, emotional, and cognitive aspects of pain. Herein, we briefly cover the discovery of the EC system and its role in pain processing pathways, before concentrating on three areas of current major interest in EC pain research; 1. Pharmacological enhancement of endocannabinoid activity (via blockade of EC metabolism or allosteric modulation of CB1receptors); 2. The EC System and stress-induced modulation of pain; and 3. The EC system & medial prefrontal cortex (mPFC) dysfunction in pain states. Whilst we focus predominantly on the preclinical data, we also include extensive discussion of recent clinical failures of endocannabinoid-related therapies, the future potential of these approaches, and important directions for future research on the EC system and pain.” https://www.ncbi.nlm.nih.gov/pubmed/28625720 http://www.sciencedirect.com/science/article/pii/S002839081730285X]]>
Synaptic functions of endocannabinoid signaling in health and disease.
“Endocannabinoids (eCBs) are a family of lipid molecules that act as key regulators of synaptic transmission and plasticity. They are synthetized “on demand” following physiological and/or pathological stimuli. Once released from postsynaptic neurons, eCBs typically act as retrograde messengers to activate presynaptic type 1 cannabinoid receptors (CB1) and induce short- or long-term depression of neurotransmitter release. Besides this canonical mechanism of action, recent findings have revealed a number of less conventional mechanisms by which eCBs regulate neural activity and synaptic function, suggesting that eCB-mediated plasticity is mechanistically more diverse than anticipated. These mechanisms include non-retrograde signaling, signaling via astrocytes, participation in long-term potentiation, and the involvement of mitochondrial CB1. Focusing on paradigmatic brain areas, such as hippocampus, striatum, and neocortex, we review typical and novel signaling mechanisms, and discuss the functional implications in normal brain function and brain diseases. In summary, eCB signaling may lead to different forms of synaptic plasticity through activation of a plethora of mechanisms, which provide further complexity to the functional consequences of eCB signaling.” https://www.ncbi.nlm.nih.gov/pubmed/28625718 http://www.sciencedirect.com/science/article/pii/S0028390817302861]]>
Metabolism of the Endocannabinoid Anandamide: Open Questions after 25 Years.
“Cannabis extracts have been used for centuries, but its main active principle ∆9-tetrahydrocannabinol (THC) was identified about 50 years ago. Yet, it is only 25 years ago that the first endogenous ligand of the same receptors engaged by the cannabis agents was discovered. This “endocannabinoid (eCB)” was identified as N-arachidonoylethanolamine (or anandamide (AEA)), and was shown to have several receptors, metabolic enzymes and transporters that altogether drive its biological activity. Here I report on the latest advances about AEA metabolism, with the aim of focusing open questions still awaiting an answer for a deeper understanding of AEA activity, and for translating AEA-based drugs into novel therapeutics for human diseases.”
https://www.ncbi.nlm.nih.gov/pubmed/28611591
Endocannabinoid System in Neurodegenerative Disorders.
“Most neurodegenerative disorders (NDDs) are characterized by cognitive impairment and other neurological defects. The definite cause of and pathways underlying the progression of these NDDs are not well defined. Several mechanisms have been proposed to contribute to the development of NDDs. These mechanisms may proceed concurrently or successively, and they differ among cell types at different developmental stages in distinct brain regions. The endocannabinoid system, which involves cannabinoid receptors type 1 (CB1R) and type 2 (CB2R), endogenous cannabinoids and the enzymes that catabolize these compounds, has been shown to contribute to the development of NDDs in several animal models and human studies. In this review, we discuss the functions of the endocannabinoid (EC) system in NDDs and converse the therapeutic efficacy of targeting the endocannabinoid system to rescue NDDs.” https://www.ncbi.nlm.nih.gov/pubmed/28608560 http://onlinelibrary.wiley.com/doi/10.1111/jnc.14098/abstract]]>
Cannabidiol upregulates melanogenesis through CB1 dependent pathway by activating p38 MAPK and p42/44 MAPK.
“Melanogenesis plays a critical role in the protection of skin against external stresses such as ultraviolet irradiation and oxidative stressors. This study was aimed to investigate the effects of cannabidiol on melanogenesis and its mechanisms of action in human epidermal melanocytes. We found that cannabidiol increased both melanin content and tryrosinase activity. The mRNA levels of microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein (TRP) 1, and TRP2 were increased following cannabidiol treatment. Likewise, cannabidiol increased the protein levels of MITF, TRP 1, TRP 2, and tyrosinase. Mechanistically, we found that cannabidiol regulated melanogenesis by upregulating MITF through phosphorylation of p38 mitogen-activated protein kinase (MAPK) and p42/44 MAPK, independent of cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) signaling. In addition, the melanogenic effect of cannabidiol was found to be mediated by cannabinoid CB1 receptor, not by CB2receptor. Taken together, these findings indicate that cannabidiol-induced melanogenesis is cannabinoid CB1 receptor-dependent, and cannabidiol induces melanogenesis through increasing MITF gene expression which is mediated by activation of p38 MAPK and p42/44 MAPK. Our results suggest that cannabidiol might be useful as a protective agent against external stresses.” https://www.ncbi.nlm.nih.gov/pubmed/28601556 http://www.sciencedirect.com/science/article/pii/S0009279716304343]]>
Medicinal Uses of Marijuana and Cannabinoids
“In the past two decades, there has been increasing interest in the therapeutic potential of cannabis and single cannabinoids, mainly cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC). THC and cannabis products rich in THC exert their effects mainly through the activation of cannabinoid receptors (CB1 and CB2). Since 1975, 140 controlled clinical trials using different cannabinoids or whole-plant preparations for the treatment of a large number of disorders and symptoms have been conducted. Results have led to the approval of cannabis-based medicines [dronabinol, nabilone, and the cannabis extract nabiximols (Sativex®, THC:CBD = 1:1)] as well as cannabis flowers in several countries. Controlled clinical studies provide substantial evidence for the use of cannabinoid receptor agonists in cancer chemotherapy induced nausea and vomiting, appetite loss and cachexia in cancer and HIV patients, neuropathic and chronic pain, and in spasticity in multiple sclerosis. In addition, there is also some evidence suggesting a therapeutic potential of cannabis-based medicines in other indications including Tourette syndrome, spinal cord injury, Crohn’s disease, irritable bowel syndrome, and glaucoma. In several other indications, small uncontrolled and single-case studies reporting beneficial effects are available, for example in posttraumatic stress disorder, attention deficit hyperactivity disorder, and migraine. The most common side effects of THC and cannabis-based medicines rich in THC are sedation and dizziness (in more than 10% of patients), psychological effects, and dry mouth. Tolerance to these side effects nearly always develops within a short time. Withdrawal symptoms are hardly ever a problem in the therapeutic setting. In recent years there is an increasing interest in the medical use of CBD, which exerts no intoxicating side effects and is usually well-tolerated. Preliminary data suggest promising effects in the treatment of anxiety disorders, schizophrenia, dystonia, and some forms of epilepsy. This review gives an overview on clinical studies which have been published over the past 40 years.” http://www.tandfonline.com/doi/abs/10.1080/07352689.2016.1265360?needAccess=true&journalCode=bpts20
“Review Identifies 140 Controlled Clinical Trials Related to Cannabis” http://blog.norml.org/2017/06/04/review-identifies-140-controlled-clinical-trials-related-to-cannabis/
]]>Analysis of Natural Product Regulation of Cannabinoid Receptors in the treatment of Human Disease.
“The organized tightly regulated signaling relays engaged by the cannabinoid receptors (CBs) and their ligands, G proteins and other effectors, together constitute the endocannabinoid system (ECS). This system governs many biological functions including cell proliferation, regulation of ion transport and neuronal messaging. This review will firstly examine the physiology of the ECS, briefly discussing some anomalies in the relay of the ECS signaling as these are consequently linked to maladies of global concern including neurological disorders, cardiovascular disease and cancer. While endogenous ligands are crucial for dispatching messages through the ECS, there are also commonalities in binding affinities with copious exogenous ligands, both natural and synthetic. Therefore, this review provides a comparative analysis of both types of exogenous ligands with emphasis on natural products given their putative safer efficacy and the role of Δ9-tetrahydrocannabinol (Δ9-THC) in uncovering the ECS. Efficacy is congruent to both types of compounds but noteworthy is the effect of a combination therapy to achieve efficacy without the unideal side-effects. An example is Sativex that displayed promise in treating Huntington’s disease (HD) in preclinical models allowing for its transition to current clinical investigation. Despite the in vitro and preclinical efficacy of Δ9-THC to treat neurodegenerative ailments, its psychotropic effects limit its clinical applicability to treating feeding disorders. We therefore propose further investigation of other compounds and their combinations such as the triterpene, α,β-amyrin that exhibited greater binding affinity to CB1 than CB2 and was more potent than Δ9-THC and the N-alkylamides that exhibited CB2 selective affinity, the latter can be explored towards peripherally exclusive ECS modulation. The synthetic CB1 antagonist, Rimonabant was pulled from market for the treatment of diabetes, however its analogue SR144528 maybe an ideal lead molecule towards this end and HU-210 and Org27569 are also promising synthetic small molecules.” https://www.ncbi.nlm.nih.gov/pubmed/28583800 http://www.sciencedirect.com/science/article/pii/S0163725817301511]]>
Cannabinoids in attention-deficit/hyperactivity disorder: A randomised-controlled trial.
“Adults with ADHD describe self-medicating with cannabis, with some reporting a preference for cannabis over ADHD medications. A small number of psychiatrists in the US prescribe cannabis medication for ADHD, despite there being no evidence from randomised controlled studies. The EMA-C trial (Experimental Medicine in ADHD-Cannabinoids) was a pilot randomised placebo-controlled experimental study of a cannabinoid medication, Sativex Oromucosal Spray, in 30 adults with ADHD. Adults with ADHD may represent a subgroup of individuals who experience a reduction of symptoms and no cognitive impairments following cannabinoid use. While not definitive, this study provides preliminary evidence supporting the self-medication theory of cannabis use in ADHD and the need for further studies of the endocannabinoid system in ADHD.” https://www.ncbi.nlm.nih.gov/pubmed/28576350 http://www.europeanneuropsychopharmacology.com/article/S0924-977X(17)30237-7/fulltext]]>