Peripherally selective cannabinoid 1 receptor (CB1R) agonists for the treatment of neuropathic pain

 Journal of Medicinal Chemistry

“Alleviation of neuropathic pain by cannabinoids is limited by their central nervous system (CNS) side effects. Indole and indene compounds were engineered for high hCB1R affinity, peripheral selectivity, metabolic stability, and in vivo efficacy. An epithelial cell line assay identified candidates with <1% blood-brain barrier penetration for testing in a rat neuropathy induced by unilateral sciatic nerve entrapment (SNE). The SNE-induced mechanical allodynia was reversibly suppressed, partially or completely, after intraperitoneal or oral administration of several indenes. At doses that relieve neuropathy symptoms, the indenes completely lacked, while the brain-permeant CB1R agonist HU-210 (1) exhibited strong CNS side effects, in catalepsy, hypothermia, and motor incoordination assays. Pharmacokinetic findings of ~0.001 cerebrospinal fluid:plasma ratio further supported limited CNS penetration. Pretreatment with selective CB1R or CB2R blockers suggested mainly CB1R contribution to an indene’s anti-allodynic effects. Therefore, this class of CB1R agonists holds promise as a viable treatment for neuropathic pain.”

http://pubs.acs.org/doi/abs/10.1021/acs.jmedchem.6b00516

Expression of Cannabinoid Receptors in Human Osteoarthritic Cartilage: Implications for Future Therapies

“Cannabinoids have shown to reduce joint damage in animal models of arthritis and reduce matrix metalloproteinase expression in primary human osteoarthritic (OA) chondrocytes.

Chondrocytes from OA joints were shown to express a wide range of cannabinoid receptors even in degenerate tissues, demonstrating that these cells could respond to cannabinoids.

Cannabinoids designed to bind to receptors inhibiting the catabolic and pain pathways within the arthritic joint, while avoiding psychoactive effects, could provide potential arthritis therapies.

Cannabinoids were originally derived from the cannabis plant, Cannabis sativa, which has been used medicinally and recreationally for many years because of its anti-inflammatory, analgesic, and psychoactive properties.”

http://online.liebertpub.com/doi/full/10.1089/can.2015.0001

Endocannabinoids: new targets for drug development.

“The possible therapeutic use of marijuana s active principles, the cannabinoids, is currently being debated.

It is now known that these substances exert several of their pharmacological actions by activating specific cell membrane receptors, the CB1 and CB2 cannabinoid receptor subtypes.

This knowledge led to the design of synthetic cannabinoid agonists and antagonists with high therapeutic potential.

The recent discovery of the endocannabinoids, i.e. endogenous metabolites capable of activating the cannabinoid receptors, and the understanding of the molecular mechanisms leading to their biosynthesis and inactivation, opened a new era in research on the pharmaceutical applications of cannabinoids.

Ongoing studies on the pathological and physiological conditions regulating the tissue levels of endocannabinoids, and on the pharmacological activity of these compounds and their derivatives, may provide a lead for the development of new drugs for the treatment of nervous and immune disorders, cardiovascular diseases, pain, inflammation and cancer.

These studies are reviewed in this article with special emphasis on the chemical features that determine the interaction of endocannabinoids with the proteins mediating their activity and degradation.”

http://www.ncbi.nlm.nih.gov/pubmed/10903398

Cannabinoids biology: the search for new therapeutic targets.

“Cannabinoids, in the form of marijuana plant extracts, have been used for thousands of years for a wide variety of medical conditions, ranging from general malaise and mood disorders to more specific ailments, such as pain, nausea, and muscle spasms.

The discovery of tetrahydrocannabinol, the active principal in marijuana, and the identification and cloning of two cannabinoid receptors (i.e., CB1 and CB2) has subsequently led to biomedical appreciation for a family of endocannabinoid lipid transmitters.

The biosynthesis and catabolism of the endocannabinoids and growing knowledge of their broad physiological roles are providing insight into potentially novel therapeutic targets.

Compounds directed at one or more of these targets may allow for cannabinoid-based therapeutics with limited side effects and abuse liability.”

http://www.ncbi.nlm.nih.gov/pubmed/16809476

Arthritis and cannabinoids: HU-210 and Win-55,212-2 prevent IL-1alpha-induced matrix degradation in bovine articular chondrocytes in-vitro.

 

“Cannabinoids have analgesic, immunomodulatory and anti-inflammatory properties and attenuate joint damage in animal models of arthritis.

Chondrocytes appeared to constitutively express cannabinoid receptors CB1 and CB2.

It is concluded that biologically stable synthetic cannabinoids protect cartilage matrix from degradation induced by cytokines and this effect is possibly CB-receptor mediated and involves effects on prostaglandin and nitric oxide metabolism.”

http://www.ncbi.nlm.nih.gov/pubmed/16536902

The future of cannabinoids as analgesic agents: a pharmacologic, pharmacokinetic, and pharmacodynamic overview.

 

“For thousands of years, physicians and their patients employed cannabis as a therapeutic agent.

Despite this extensive historical usage, in the Western world, cannabis fell into disfavor among medical professionals because the technology available in the 1800s and early 1900s did not permit reliable, standardized preparations to be developed.

However, since the discovery and cloning of cannabinoid receptors (CB1 and CB2) in the 1990s, scientific interest in the area has burgeoned, and the complexities of this fascinating receptor system, and its endogenous ligands, have been actively explored.

Recent studies reveal that cannabinoids have a rich pharmacology and may interact with a number of other receptor systems-as well as with other cannabinoids-to produce potential synergies.

Cannabinoids-endocannabinoids, phytocannabinoids, and synthetic cannabinoids-affect numerous bodily functions and have indicated efficacy of varying degrees in a number of serious medical conditions.

Cannabinoid receptor agonists and/or molecules that affect the modulation of endocannabinoid synthesis, metabolism, and transport may, in the future, offer extremely valuable tools for the treatment of a number of currently intractable disorders.”

 http://www.ncbi.nlm.nih.gov/pubmed/17890938

Refractory trigeminal neuralgia responsive to nabiximols in a patient with multiple sclerosis.

“Nabiximols is a cannabinoid compound approved for the treatment of multiple sclerosis (MS)-related spasticity.

However, additional symptoms, such as pain, urinary urgency and sleep disturbance, may benefit from treatment.

CASE REPORT:

The present report describes a patient with secondary progressive MS and severe lower limbs spasticity who was started on treatment with nabiximols. The patient also suffered from trigeminal neuralgia, which he was not treating due to inefficacy or side effects of all previously tried medications. After nabiximols initiation the patient experienced a marked benefit on trigeminal neuralgia, which completely resolved, while spasticity responded only partially to treatment.

CONCLUSION:

Nabiximols mechanism of action is based on the interaction with CB1 and CB2 receptors, which are expressed by central nervous system neurons and are known to modulate pain among other effects. The present case indicates that nabiximols and other cannabinoids need to be further tested for the treatment of trigeminal neuralgia.”

http://www.ncbi.nlm.nih.gov/pubmed/27456876

“Therapeutic potential of cannabinoids in trigeminal neuralgia. Considering the pronounced antinociceptive effects produced by cannabinoids, they may be a promising therapeutic approach for the clinical management of trigeminal neuralgia.”  http://www.ncbi.nlm.nih.gov/pubmed/15578967

Crucial Roles of the Endocannabinoid 2-Arachidonoylglycerol in the Suppression of Epileptic Seizures.

“Endocannabinoid signaling is considered to suppress excessive excitability of neural circuits and to protect the brain from seizures. However, the precise mechanisms of this effect are poorly understood.

Here, we report that 2-arachidonoylglycerol (2-AG), one of the two major endocannabinoids, is crucial for suppressing seizures.

We found that kainate-induced seizures in mice lacking the 2-AG synthesizing enzyme, diacylglycerol lipase α, were much more severe compared with those in cannabinoid CB1 receptor knockout mice and were comparable to those in mice lacking both CB1– and CB2-receptor-mediated signaling.

In the dentate gyrus, 2-AG suppressed excitatory input around the inner and middle molecular layers through CB1 and presumably CB2 receptors, respectively.

This 2-AG-mediated suppression contributed to decreased granule cell excitability and the dampening of seizures. Furthermore, lack of 2-AG signaling enhanced kindling epileptogenesis and spontaneous seizures after kainate-induced status epilepticus.

These results highlight critical roles of 2-AG signaling in the suppression of epileptic seizures.”

http://www.ncbi.nlm.nih.gov/pubmed/27452464

Cannabinoid Modulation of Cutaneous Aδ Nociceptors During Inflammation

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“Previous studies have demonstrated that locally administered cannabinoids attenuate allodynia and hyperalgesia through activation of peripheral cannabinoid receptors (CB1 and CB2).

These results suggest that attenuation of mechanically evoked responses of Aδ nociceptors contributes to the behavioral antinociception produced by activation of peripheral CB1 receptors during inflammation.

Several studies have demonstrated that locally administered cannabinoids produce antinociception in animal models of both acute and persistent pain through peripheral mechanisms.

Taken together, our data suggest that peripherally acting cannabinoids could be a potential therapeutic treatment for chronic inflammatory pain.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2585399/

 

Enantiomeric cannabidiol derivatives: synthesis and binding to cannabinoid receptors.

“(-)-Cannabidiol (CBD) is a major, non psychotropic constituent of cannabis.

It has been shown to cause numerous physiological effects of therapeutic importance.

We have reported that CBD derivatives in both enantiomeric series are of pharmaceutical interest. Here we describe the syntheses of the major CBD metabolites, (-)-7-hydroxy-CBD and (-)-CBD-7-oic acid and their dimethylheptyl (DMH) homologs, as well as of the corresponding compounds in the enantiomeric (+)-CBD series. The starting materials were the respective CBD enantiomers and their DMH homologs.

The binding of these compounds to the CB(1) and CB(2) cannabinoid receptors are compared.

Surprisingly, contrary to the compounds in the (-) series, which do not bind to the receptors, most of the derivatives in the (+) series bind to the CB(1) receptor in the low nanomole range. Some of these compounds also bind weakly to the CB(2) receptor.”

http://www.ncbi.nlm.nih.gov/pubmed/15750656