“Prion diseases are neurodegenerative disorders characterized by deposition of the pathological prion protein (PrPsc) within the brain of affected humans and animals. Microglial cell activation is a common feature of prion diseases; alterations of various neurotransmitter systems and neurotransmission have been also reported. Owing to its ability to modulate both neuroimmune responses and neurotransmission, it was of interest to study the brain endocannabinoid system in a prion-infected mouse model. The production of the endocannabinoid, 2-arachidonoyglycerol (2-AG), was enhanced 10 weeks post-infection, without alteration of the other endocannabinoid, anandamide. The CB2 receptor expression was up-regulated in brains of prion-infected mice as early as 10 weeks and up to 32 weeks post-infection whereas the mRNAs of other cannabinoid receptors (CBRs) remain unchanged. The observed alterations of the endocannabinoid system were specific for prion infection since no significant changes were observed in the brain of prion-resistant mice, that is, mice devoid of the Prnp gene. Our study highlights important alterations of the endocannabinoid system during early stages of the disease long before the clinical signs of the disease.” https://www.ncbi.nlm.nih.gov/pubmed/21195746
Category Archives: Endocannabinoid System
Pharmacology of cannabinoids in the treatment of epilepsy.
“The use of cannabis products in the treatment of epilepsy has long been of interest to researchers and clinicians alike; however, until recently very little published data were available to support its use. This article summarizes the available scientific data of pharmacology from human and animal studies on the major cannabinoids which have been of interest in the treatment of epilepsy, including ∆9-tetrahydrocannabinol (∆9-THC), cannabidiol (CBD), ∆9-tetrahydrocannabivarin (∆9-THCV), cannabidivarin (CBDV), and ∆9-tetrahydrocannabinolic acid (Δ9-THCA). It has long been known that ∆9-THC has partial agonist activity at the endocannabinoid receptors CB1 and CB2, though it also binds to other targets which may modulate neuronal excitability and neuroinflammation. The actions of Δ9-THCV and Δ9-THCA are less well understood. In contrast to ∆9-THC, CBD has low affinity for CB1 and CB2 receptors and other targets have been investigated to explain its anticonvulsant properties including TRPV1, voltage gated potassium and sodium channels, and GPR55, among others. We describe the absorption, distribution, metabolism, and excretion of each of the above mentioned compounds. Cannabinoids as a whole are very lipophilic, resulting in decreased bioavailability, which presents challenges in optimal drug delivery. Finally, we discuss the limited drug-drug interaction data available on THC and CBD. As cannabinoids and cannabis-based products are studied for efficacy as anticonvulsants, more investigation is needed regarding the specific targets of action, optimal drug delivery, and potential drug-drug interactions.” https://www.ncbi.nlm.nih.gov/pubmed/28087250]]>
Developmental Role of Macrophage Cannabinoid-1 Receptor Signaling in Type-2 Diabetes.
“Islet inflammation promotes β-cell loss and type-2 diabetes (T2D), a process replicated in Zucker Diabetic Fatty (ZDF) rats in which β-cell loss has been linked to cannabinoid-1 receptor (CB1R)-induced pro-inflammatory signaling in macrophages infiltrating pancreatic islets. Here, we analyzed CB1R signaling in macrophages and its developmental role in T2Dα. ZDF rats with global deletion of CB1R are protected from β-cell loss, hyperglycemia and nephropathy present in ZDF littermates. Adoptive transfer of CB1R-/- bone marrow to ZDF rats also prevents β-cell loss and hyperglycemia, but not nephropathy. ZDF islets contain elevated levels of CB1R, IL-1β, TNF-α, the chemokine CCL2 and interferon regulatory factor-5 (IRF5), a marker of M1 inflammatory macrophage polarization. In primary cultured rodent and human macrophages, CB1R activation increased Irf5 expression, whereas knockdown of Irf5 blunted CB1R-induced secretion of inflammatory cytokines without affecting CCL2 expression, which was p38MAPKα-dependent. Macrophage-specific in vivo knockdown of Irf5 protected ZDF rats from β-cell loss and hyperglycemia. Thus, IRF5 is a crucial downstream mediator of diabetogenic CB1R signaling in macrophages and a potential therapeutic target.” https://www.ncbi.nlm.nih.gov/pubmed/28082458]]>
Manipulation of the Endocannabinoid System in Colitis: A Comprehensive Review.
“Inflammatory bowel disease (IBD) is a lifelong disease of the gastrointestinal tract whose annual incidence and prevalence is on the rise. Current immunosuppressive therapies available for treatment of IBD offer limited benefits and lose effectiveness, exposing a significant need for the development of novel therapies. In the clinical setting, cannabis has been shown to provide patients with IBD symptomatic relief, although the underlying mechanisms of their anti-inflammatory effects remain unclear.
RESULTS:
Cannabinoid receptors 1 and 2, endogenous cannabinoids, and atypical cannabinoids are upregulated in inflammation, and their presence and stimulation attenuate murine colitis, whereas cannabinoid receptor antagonism and cannabinoid receptor deficient models reverse these anti-inflammatory effects. In addition, inhibition of endocannabinoid degradation through monoacylglycerol lipase and fatty acid amide hydrolase blockade can also attenuate colitis development, and is closely linked to cannabinoid receptor expression.CONCLUSIONS:
Although manipulation of the endocannabinoid system in murine colitis has proven to be largely beneficial in attenuating inflammation, there is a paucity of human study data. Further research is essential to clearly elucidate the specific mechanisms driving this anti-inflammatory effect for the development of therapeutics to target inflammatory disease such as IBD.” https://www.ncbi.nlm.nih.gov/pubmed/28079617 “Plant cannabinoids THC and CBD proved beneficial in DNBS-induced colitis in a bell-shaped dose-related response, but more importantly, the effects of the phytocannabinoids were additive, as CBD increased an ineffective THC dose to the level of an effective one.” https://academic.oup.com/ibdjournal/article/23/2/192/4347176Up-regulation of CB2 receptors in reactive astrocytes in canine degenerative myelopathy, a disease model of amyotrophic lateral sclerosis.
“Targeting the CB2 receptor afforded neuroprotection in SOD1G93A mutant mice, a model of amyotrophic lateral sclerosis (ALS). The neuroprotective effects of CB2 receptors were facilitated by their up-regulation in the spinal cord in SOD1G93A mutant mice. Herein, we have investigated whether a similar CB2 receptor up-regulation, as well as parallel changes in other endocannabinoid elements, are evident in the spinal cord of dogs with degenerative myelopathy (DM), caused from mutations in the superoxide dismutase 1 gene (SOD1). In summary, our results demonstrated a marked up-regulation of CB2 receptors occurring in the spinal cord in canine DM, which was concentrated in activated astrocytes. Such receptors may be used as a potential target to enhance the neuroprotective effects exerted by these glial cells.” https://www.ncbi.nlm.nih.gov/pubmed/28069688]]>
Brain cannabinoid receptor 2: expression, function and modulation.
“Cannabis sativa (marijuana) is a fibrous flowering plant that produces an abundant variety of molecules, some with psychoactive effects. At least 4% of the world’s adult population uses cannabis annually, making it one of the most frequently used illicit drugs in the world. The psychoactive effects of cannabis are mediated primarily through cannabinoid receptor (CBR) subtypes. The prevailing view is that CB1Rs are mainly expressed in the central neurons, whereas CB2Rs are predominantly expressed in peripheral immune cells. However, this traditional view has been challenged by emerging strong evidence that shows CB2Rs are moderately expressed and function in specific brain areas. New evidence has demonstrated that brain CB2Rs modulate animal drug-seeking behaviors, suggesting that these receptors may exist in brain regions that regulate drug addiction. Recently, we further confirmed that functional CB2Rs are expressed in mouse ventral tegmental area (VTA) dopamine (DA) neurons and that the activation of VTA CB2Rs reduces neuronal excitability and cocaine-seeking behavior. In addition, CB2R-mediated modulation of hippocampal CA3 neuronal excitability and network synchronization has been reported. Here, we briefly summarize recent lines of evidence showing how CB2Rs modulate function and pathophysiology in the CNS.”
https://www.ncbi.nlm.nih.gov/pubmed/28065934
“Recent evidence shows that the endocannabinoid system is involved in the pathogenesis of numerous neurodegenerative diseases of the central nervous system. Pharmacologic modulation of 