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]]>

The orphan receptor GPR55 is a novel cannabinoid receptor

“Preparations of Cannabis sativa have been used for medicinal and recreational purposes for at least 4000 years and extracts of C. sativa contain over 60 different pharmacologically active components the most prominent being Δ9-tetrahydrocannabinol (Δ9-THC) and cannabidiol Ligands such as cannabidiol and abnormal cannabidiol which exhibit no CB1or CB2 activity and are believed to function at a novel cannabinoid receptor, also showed activity at GPR55.

These data suggest that GPR55 is a novel cannabinoid receptor, and its ligand profile with respect to CB1and CB2 described here will permit delineation of its physiological function(s).”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2095107/

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The effect of Pro NanoLipospheres (PNL) formulation containing natural absorption enhancers on the oral bioavailability of delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) in a rat model.

“The lipophilic phytocannabinoids cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC) show therapeutic efficacy in various medical conditions. Both molecules are poorly water soluble and subjected to extensive first pass metabolism in the gastrointestinal tract, leading to a limited oral bioavailability of approximately 9%. We have developed an advanced lipid based Self-Emulsifying Drug Delivery System termed Advanced Pro-NanoLiposphere (PNL) pre-concentrate. The PNL is composed of lipid and emulsifying excipients of GRAS status and are known to increase solubility and reduce Phase I metabolism of lipophilic active compounds. Advanced PNLs are PNLs with an incorporated natural absorption enhancers. These molecules are natural alkaloids and phenolic compounds which were reported to inhibit certain phase I and phase II metabolism processes. Here we use piperine, curcumin and resveratrol to formulate the Advanced-PNL formulations. Consequently, we have explored the utility of these Advanced-PNLs on CBD and THC oral bioavailability. Oral administration of CBD-piperine-PNL resulted in 6-fold in AUC compared to CBD solution, proving to be the most effective of the screened formulations. The same trend was found in pharmacokinetic experiments of THC-piperine-PNL with resulted in a 9.3-fold increase in AUC as compared to THC solution. Our Piperine-PNL can be used as a platform for synchronized delivery of piperine and CBD or THC to the enterocyte site. This co-localization provides an increase in CBD and THC bioavailability by its effect at the pre-enterocyte and the enterocyte levels of the absorption process. The extra augmentation in the absorption of CBD and THC by incorporating piperine into PNL is attributed to the inhibition of Phase I and phase II metabolism by piperine in addition to the Phase I metabolism and P-gp inhibition by PNL. These novel results pave the way to utilize piperine-PNL delivery system for other poorly soluble, highly metabolized compounds that currently cannot be administered orally.” https://www.ncbi.nlm.nih.gov/pubmed/28736128 http://www.sciencedirect.com/science/article/pii/S0928098717304025]]>

Delta-9-tetrahydrocannabinol decreases masticatory muscle sensitization in female rats through peripheral cannabinoid receptor activation.

“This study investigated whether intramuscular injection of delta-9-tetrahydrocannabinol (THC), by acting on peripheral cannabinoid (CB) receptors, could decrease nerve growth factor (NGF)-induced sensitization in female rat masseter muscle; a model which mimics the symptoms of myofascial temporomandibular disorders.

It was found that CB1 and CB2 receptors are expressed by trigeminal ganglion neurons that innervate the masseter muscle and also on their peripheral endings.

These results suggest that reduced inhibitory input from the peripheral cannabinoid system may contribute to NGF-induced local myofascial sensitization of mechanoreceptors. Peripheral application of THC may counter this effect by activating the CB1 receptors on masseter muscle mechanoreceptors to provide analgesic relief without central side effects.

SIGNIFICANCE:

Our results suggest THC could reduce masticatory muscle pain through activating peripheral CB1 receptors. Peripheral application of cannabinoids could be a novel approach to provide analgesic relief without central side effects.” https://www.ncbi.nlm.nih.gov/pubmed/28722246 http://onlinelibrary.wiley.com/doi/10.1002/ejp.1085/abstract]]>

Amyloid proteotoxicity initiates an inflammatory response blocked by cannabinoids.

“The beta amyloid (Aβ) and other aggregating proteins in the brain increase with age and are frequently found within neurons. The mechanistic relationship between intracellular amyloid, aging and neurodegeneration is not, however, well understood. We use a proteotoxicity model based upon the inducible expression of Aβ in a human central nervous system nerve cell line to characterize a distinct form of nerve cell death caused by intracellular Aβ. It is shown that intracellular Aβ initiates a toxic inflammatory response leading to the cell’s demise. Aβ induces the expression of multiple proinflammatory genes and an increase in both arachidonic acid and eicosanoids, including prostaglandins that are neuroprotective and leukotrienes that potentiate death. Cannabinoids such as tetrahydrocannabinol stimulate the removal of intraneuronal Aβ, block the inflammatory response, and are protective. Altogether these data show that there is a complex and likely autocatalytic inflammatory response within nerve cells caused by the accumulation of intracellular Aβ, and that this early form of proteotoxicity can be blocked by the activation of cannabinoid receptors.”
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