“Of the druggable group of G protein-coupled receptors in the human genome, a number remain which have yet to be paired with an endogenous ligand-orphan GPCRs. Among these 100 or so entities, 3 have been linked to the cannabinoid system. GPR18, GPR55, and GPR119 exhibit limited sequence homology with the established CB1 and CB2 cannabinoid receptors. However, the pharmacology of these orphan receptors displays overlap with CB1 and CB2 receptors, particularly for GPR18 and GPR55. The linking of GPR119 to the cannabinoid receptors is less convincing and emanates from structural similarities of endogenous ligands active at these GPCRs, but which do not cross-react. This review describes the evidence for describing these orphan GPCRs as cannabinoid receptor-like receptors.” https://www.ncbi.nlm.nih.gov/pubmed/28826536 http://www.sciencedirect.com/science/article/pii/S1054358917300418?via%3Dihub]]>
Actions and Regulation of Ionotropic Cannabinoid Receptors.
2+, Na+, and various type of K+ channels), ligand-gated ion channels (i.e., GABA, glycine), and ion-transporting membranes proteins such as transient potential receptor class (TRP) channels. The first direct, cannabinoid receptor-independent interaction was reported on the function of serotonin 5-HT3 receptor-ion channel complex. Similar effects were reported also on the other above mentioned ion channels. In the early ninety, studies searching for endogenous modulators of L-type Ca2+ channels identified anandamide as ligand for L-type Ca2+ channel. Later investigations indicated that other types of Ca2+ currents are also affected by endocannabinoids, and, in the late ninety, it was discovered that endocannabinoids activate the vanilloid receptor subtype 1 (TRPV1), and nowadays, it is known that (endo)cannabinoids gate at least five distinct TRP channels. This chapter focuses on cannabinoid regulation of ion channels and lays special emphasis on their action at transient receptor channels.” https://www.ncbi.nlm.nih.gov/pubmed/28826537]]>
Functional Selectivity at Cannabinoid Receptors.
“It is now clear that, in contrast to traditional descriptions of G protein-coupled receptor signaling, agonists can activate or inhibit characteristic patterns of downstream effector pathways depending on their structures and the conformational changes induced in the receptor. This is referred to as functional selectivity (also known as agonist-directed trafficking, ligand-induced differential signaling, or biased agonism). It is important because even small structural differences can result in significant variations in overall agonist effects (wanted and unwanted) depending on which postreceptor signaling systems are engaged by each agonist/receptor pairing. In addition to the canonical signaling pathways mediated by Gi/o proteins, CB1 and CB2 receptor agonists can have effects via differential activation not only of Gi subtypes but also of Gs and Gq/11 proteins. For example, the classical cannabinoid HU-210 produces maximal activation of both Gi and Go proteins, while the endocannabinoid anandamide and aminoalkylindole WIN 55,212 both produce maximal activation of Gi, but submaximal activation of Go. Cannabinoid agonists can also signal differentially via β-arrestins coupled to mitogen-activated protein kinases, subsequently promoting varying degrees of receptor internalization and agonist desensitization. A recent extensive characterization of the molecular pharmacology of CB2 agonists (Soethoudt et al., 2017) identified marked differences (bias) in the ability of certain agonists to activate distinct signaling pathways (cAMP accumulation, ERK phosphorylation, GIRK activation, GTPγS binding, and β-arrestin recruitment) and to cause off-target effects, exemplifying the need to evaluate functional selectivity in agonist drug development.” https://www.ncbi.nlm.nih.gov/pubmed/28826535 http://www.sciencedirect.com/science/article/pii/S1054358917300285?via%3Dihub]]>
CB1 and CB2 Receptor Pharmacology.
“The CB1 and CB2 cannabinoid receptors (CB1R, CB2R) are members of the G protein-coupled receptor (GPCR) family that were identified over 20 years ago. CB1Rs and CB2Rs mediate the effects of Δ9-tetrahydrocannabinol (Δ9-THC), the principal psychoactive constituent of marijuana, and subsequently identified endogenous cannabinoids (endocannabinoids) anandamide and 2-arachidonoyl glycerol. CB1Rs and CB2Rs have both similarities and differences in their pharmacology. Both receptors recognize multiple classes of agonist and antagonist compounds and produce an array of distinct downstream effects. Natural polymorphisms and alternative splice variants may also contribute to their pharmacological diversity. As our knowledge of the distinct differences grows, we may be able to target select receptor conformations and their corresponding pharmacological responses. This chapter will discuss their pharmacological characterization, distribution, phylogeny, and signaling pathways. In addition, the effects of extended agonist exposure and how that affects signaling and expression patterns of the receptors are considered.” https://www.ncbi.nlm.nih.gov/pubmed/28826534 http://www.sciencedirect.com/science/article/pii/S1054358917300340?via%3Dihub]]>
Endocannabinoid Analytical Methodologies: Techniques That Drive Discoveries That Drive Techniques.
“Identification of the two major endogenous cannabinoid ligands, known as endocannabinoids, N-arachidonoyl-ethanolamine (anandamide, AEA) and 2-arachidonoyl-glycerol (2-AG), opened the way for the identification and isolation of other lipid congeners, all derivatives of fatty acids and related to the Endocannabinoid System. The nomenclature of this anandamide-type class of lipids is evolving as new species are discovered all the time. However, they each fall under the larger umbrella of lipids that are a conjugation of a fatty acid with an amine through and amide bond, which we will refer to as lipoamines. Specific subspecies of lipoamines that have been discovered are the N-acyl-ethanolamides (including AEA), N-acyl-dopamines, N-acyl-serotonins, N-acyl-GABA, N-acyl-taurines, and a growing number of N-acyl amino acids. Emerging data from multiple labs also show that monoacylglycerols (including 2-AG), COX-2 metabolites, and fatty acid esters of hydroxyl fatty acids are interconnected with these lipoamines at both the biosynthetic and metabolic levels. Understanding the molecular relatedness of these lipids is important for studying how they act as signaling molecules; however, a first step in this process hinges on advances in being able to accurately measure them.” https://www.ncbi.nlm.nih.gov/pubmed/28826532]]>
Rationale for cannabis-based interventions in the opioid overdose crisis.
“North America is currently in the grips of a crisis rooted in the use of licit and illicit opioid-based analgesics. Drug overdose is the leading cause of accidental death in Canada and the US, and the growing toll of opioid-related morbidity and mortality requires a diversity of novel therapeutic and harm reduction-based interventions.
Research suggests that increasing adult access to both medical and recreational cannabis has significant positive impacts on public health and safety as a result of substitution effect. Observational and epidemiological studies have found that medical cannabis programs are associated with a reduction in the use of opioids and associated morbidity and mortality.
The growing body of research supporting the medical use of cannabis as an adjunct or substitute for opioids creates an evidence-based rationale for governments, health care providers, and academic researchers to consider the implementation and assessment of cannabis-based interventions in the opioid crisis.”
https://www.ncbi.nlm.nih.gov/pubmed/28821296Effects of Legal Access to Cannabis on Scheduled II-V Drug Prescriptions
“Legal access to cannabis may reduce the use of multiple classes of dangerous prescription medications in certain patient populations.”“Medical Cannabis and Reduced Prescription Use. Breakthrough Study Indicates Strong Association Between Medical Cannabis and Reduced Prescription Use.” http://www.prnewswire.com/news-releases/medical-cannabis-and-reduced-prescription-use-300506774.html
“Effects of Legal Access to Cannabis on Scheduled II-V Drug Prescriptions. Legal access to cannabis may reduce the use of multiple classes of dangerous prescription medications in certain patient populations.” https://www.ncbi.nlm.nih.gov/pubmed/28899660
“Legal access to cannabis may reduce the use of multiple classes of dangerous prescription medications in certain patient populations.” http://www.jamda.com/article/S1525-8610(17)30429-2/fulltext]]>The effects of cannabinoid receptors activation and glucocorticoid receptors deactivation in the amygdala and hippocampus on the consolidation of a traumatic event.
“Ample evidence demonstrates that fear learning contributes significantly to many anxiety pathologies including post-traumatic stress disorder (PTSD). The endocannabinoid (eCB) system may offer therapeutic benefits for PTSD and it is a modulator of the hypothalamic pituitary adrenal (HPA) axis. Here we compared the separated and combined effects of blocking glucocorticoid receptors (GRs) using the GR antagonist RU486 and enhancing CB1r signaling using the CB1/2 receptor agonist WIN55,212-2 in the CA1 and basolateral amygdala (BLA) on the consolidation of traumatic memory. Traumatic memory was formed by exposure to a severe footshock in an inhibitory avoidance apparatus followed by exposure to trauma reminders. Intra-BLA RU486 (10 ng/side) and WIN55,212-2 (5 μg/side) administered immediately after shock exposure dampened the consolidation of the memory about the traumatic event and attenuated the increase in acoustic startle response in rats exposed to shock and reminders. In the CA1, WIN55,212-2 impaired consolidation and attenuated the increase in acoustic startle response whereas RU486 had no effect. The effects of WIN55,212-2 were found to be mediated by CB1 receptors, but not by GRs. Moreover, post-shock systemic WIN55,212-2 (0.5 mg/kg) administration prevented the increase in GRs and CB1 receptor levels in the CA1 and BLA in rats exposed to shock and reminders. The findings suggest that the BLA is a locus of action of cannabinoids and glucocorticoids in modulating consolidation of traumatic memory in a rat model of PTSD. Also, the findings highlight novel targets for the treatment of emotional disorders and PTSD in particular.” https://www.ncbi.nlm.nih.gov/pubmed/28818702 http://www.sciencedirect.com/science/article/pii/S1074742717301284]]>
Anticonvulsant effect of cannabidiol in the pentylenetetrazole model: Pharmacological mechanisms, electroencephalographic profile, and brain cytokine levels.
“Cannabidiol (CBD), the main nonpsychotomimetic compound from Cannabis sativa, inhibits experimental seizures in animal models and alleviates certain types of intractable epilepsies in patients. Here we tested the hypothesis that CBD anticonvulsant mechanisms are prevented by cannabinoid (CB1 and CB2) and vanilloid (TRPV1) receptor blockers. We also investigated its effects on electroencephalographic (EEG) activity and hippocampal cytokines in the pentylenetetrazole (PTZ) model. Pretreatment with CBD (60mg/kg) attenuated seizures induced by intraperitoneal, subcutaneous, and intravenous PTZ administration in mice. The effects were reversed by CB1, CB2, and TRPV1 selective antagonists (AM251, AM630, and SB366791, respectively). Additionally, CBD delayed seizure sensitization resulting from repeated PTZ administration (kindling). This cannabinoid also prevented PTZ-induced EEG activity and interleukin-6 increase in prefrontal cortex. In conclusion, the robust anticonvulsant effects of CBD may result from multiple pharmacological mechanisms, including facilitation of endocannabinoid signaling and TRPV1 mechanisms. These findings advance our understanding on CBD inhibition of seizures, EEG activity, and cytokine actions, with potential implications for the development of new treatments for certain epileptic syndromes.” https://www.ncbi.nlm.nih.gov/pubmed/28821005 http://www.epilepsybehavior.com/article/S1525-5050(17)30322-0/fulltext]]>
Topical Medical Cannabis (TMC): A new treatment for wound pain-Three cases of Pyoderma Gangrenosum.
“Pain associated with integumentary wounds is highly prevalent yet it remains an area of significant unmet need within healthcare. Currently, systemically administered opioids are the mainstay of treatment. However, recent publications are casting opioids in a negative light given their high side effect profile, inhibition of wound healing, and association with accidental overdose, incidents that are frequently fatal. Thus, novel analgesic strategies for wound-related pain need to be investigated. The ideal methods of pain relief for wound patients are modalities that are topical, lack systemic side effects, non-invasive, self-administered, and display rapid onset of analgesia. Extracts derived from the cannabis plant have been applied to wounds for thousands of years. The discovery of the human endocannabinoid system and its dominant presence throughout the integumentary system provides a valid and logical scientific platform to consider the use of topical cannabinoids for wounds. We are reporting a prospective case series of 3 patients with Pyoderma Gangrenosum (PG) that were treated with Topical Medical Cannabis (TMC) compounded in non-genetically modified organic sunflower oil. Clinically significant analgesia that was associated with reduced opioid utilization was noted in all 3 cases. TMC has the potential to improve pain management in patients suffering from wounds of all classes.” https://www.ncbi.nlm.nih.gov/pubmed/28818631 http://www.jpsmjournal.com/article/S0885-3924(17)30351-2/fulltext]]>