CB1 cannabinoid receptor activity is modulated by the cannabinoid receptor interacting protein CRIP 1a.

“The CB1 cannabinoid receptor is a G-protein coupled receptor that has important physiological roles in synaptic plasticity, analgesia, appetite, and neuroprotection.

We report the discovery of two structurally related CB1 cannabinoid receptor interacting proteins (CRIP1a and CRIP1b) that bind to the distal C-terminal tail of CB1. CRIP1a and CRIP1b are generated by alternative splicing of a gene located on chromosome 2 in humans, and orthologs of CRIP1a occur throughout the vertebrates, whereas CRIP1b seems to be unique to primates.

CRIP1a coimmunoprecipitates with CB1receptors derived from rat brain homogenates, indicating that CRIP1a and CB1 interact in vivo. Furthermore, in superior cervical ganglion neurons coinjected with CB1 and CRIP1a or CRIP1b cDNA, CRIP1a, but not CRIP1b, suppresses CB1-mediated tonic inhibition of voltage-gated Ca2+ channels.

Discovery of CRIP1a provides the basis for a new avenue of research on mechanisms of CB1 regulation in the nervous system and may lead to development of novel drugs to treat disorders where modulation of CB1 activity has therapeutic potential (e.g., chronic pain, obesity, and epilepsy).”

http://www.ncbi.nlm.nih.gov/pubmed/17895407

The Effect of Muscarinic Receptor Modulators on the Antinociception Induced by CB2 Receptor Agonist, JWH133 in Mice.

“There is no published study regarding the interaction between muscarinic receptor modulators and antinociception induced by cannabinoidreceptor (CB2) agonist. The effect of pilocarpine (a muscarinic agonist) and atropine (a muscarinic antagonist) on JWH-133 (a CB2 agonist) induced analgesia in mice was studied. First the analgesic effect of JWH-133 (0.001-1 mg/Kg) or pilocarpine (2.5-20 mg/kg) or atropine (0.2-5 mg/kg) was evaluated. Subsequently, the effect of co-administration of pilocarpine (2.5 mg/kg) or atropine (5 mg/kg) and JWH-133 (0.001-1 mg/Kg) were studied too. JWH-133 and pilocarpine provoked antinociception in mice but atropine did not. Pilocarpine potentiated the analgesic effect of JWH-133 but atropine antagonized that. It can be concluded that JWH-133 induced antinociception is affected by muscarinic receptor modulators in mice.”

http://www.ncbi.nlm.nih.gov/pubmed/27504865

Modulation of L-α-lysophosphatidylinositol/GPR55 mitogen-activated protein kinase (MAPK) signaling by cannabinoids.

“This study has implications for developing new therapeutics for the treatment of cancer, pain, and metabolic disorders.

GPR55 is activated by l-α-lysophosphatidylinositol (LPI) but also by certain cannabinoids.

In this study, we investigated the GPR55 pharmacology of various cannabinoids, including analogues of the CB1 receptor antagonist Rimonabant®, CB2 receptor agonists, and Cannabis sativa constituents.

Here, we show that CB1 receptor antagonists can act both as agonists alone and as inhibitors of LPI signaling under the same assay conditions. This study clarifies the controversy surrounding the GPR55-mediated actions of SR141716A; some reports indicate the compound to be an agonist and some report antagonism. In contrast, we report that the CB2 ligand GW405833 behaves as a partial agonist of GPR55 alone and enhances LPI signaling. GPR55 has been implicated in pain transmission, and thus our results suggest that this receptor may be responsible for some of the antinociceptive actions of certain CB2 receptor ligands.

Here, we report that the little investigated cannabis constituents CBDV, CBGA, and CBGV are potent inhibitors of LPI-induced GPR55 signaling.

The phytocannabinoids Δ9-tetrahydrocannabivarin, cannabidivarin, and cannabigerovarin are also potent inhibitors of LPI.

Our findings also suggest that GPR55 may be a new pharmacological target for the following C. sativa constituents: Δ9-THCV, CBDV, CBGA, and CBGV.

These Cannabis sativa constituents may represent novel therapeutics targeting GPR55.”  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3249141/

“Lysophosphatidylinositol (LPI) is a bioactive lipid generated by phospholipase A2 which is believed to play an important role in several diseases.”  http://www.ncbi.nlm.nih.gov/pubmed/22285325

 “The putative cannabinoid receptor GPR55 promotes cancer cell proliferation.  In this issue of Oncogene, two groups demonstrated that GPR55 is expressed in various cancer types in an aggressiveness-related manner, suggesting a novel cancer biomarker and a potential therapeutic target.” http://www.ncbi.nlm.nih.gov/pubmed/21057532
“The orphan G protein-coupled receptor GPR55 promotes cancer cell proliferation via ERK. These findings reveal the importance of GPR55 in human cancer, and suggest that it could constitute a new biomarker and therapeutic target in oncology.” http://www.ncbi.nlm.nih.gov/pubmed/20818416
“The putative cannabinoid receptor GPR55 defines a novel autocrine loop in cancer cell proliferation. These findings may have important implications for LPI as a novel cancer biomarker and for its receptor GPR55 as a potential therapeutic target.”  http://www.ncbi.nlm.nih.gov/pubmed/20838378
“L-α-lysophosphatidylinositol meets GPR55: a deadly relationship. Evidence points to a role of L-α-lysophosphatidylinositol (LPI) in cancer.”  http://www.ncbi.nlm.nih.gov/pubmed/21367464

Endocannabinoid system: Role in depression, reward and pain control (Review).

 

“Depression and pain co-exist in almost 80% of patients and are associated with impaired health-related quality of life, often contributing to high mortality. However, the majority of patients who suffer from the comorbid depression and pain are not responsive to pharmacological treatments that address either pain or depression, making this comorbidity disorder a heavy burden on patients and society.

In ancient times, this depression-pain comorbidity was treated using extracts of the Cannabis sativa plant, known now as marijuana and the mode of action of Δ9‑tetrahydrocannabinol, the active cannabinoid ingredient of marijuana, has only recently become known, with the identification of cannabinoidreceptor type 1 (CB1) and CB2.

Subsequent investigations led to the identification of endocannabinoids, anandamide and 2-arachidonoylglycerol, which exert cannabinomimetic effects through the CB1 and CB2 receptors, which are located on presynaptic membranes in the central nervous system and in peripheral tissues, respectively.

These endocannabinoids are produced from membrane lipids and are lipohilic molecules that are synthesized on demand and are eliminated rapidly after their usage by hydrolyzing enzymes.

Clinical studies revealed altered endocannabinoid signaling in patients with chronic pain.

Considerable evidence suggested the involvement of the endocannabinoid system in eliciting potent effects on neurotransmission, neuroendocrine, and inflammatory processes, which are known to be deranged in depression and chronic pain.

Several synthetic cannabinomimetic drugs are being developed to treat pain and depression. However, the precise mode of action of endocannabinoids on different targets in the body and whether their effects on pain and depression follow the same or different pathways, remains to be determined.”

http://www.ncbi.nlm.nih.gov/pubmed/27484193

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

Characterization of delta9-tetrahydrocannabinol and anandamide antinociception in nonarthritic and arthritic rats.

“The hypothesis was tested that THC and anandamide elicit antinociception in the paw pressure test, and that arthritic rats would exhibit a different response.

THC and anandamide appear to release an as yet unknown endogenous opioid, because naloxone significantly blocked their effects.

This study indicates that anandamide and THC may act at different receptor sites to modulate endogenous opioid levels in mechanical nociception.”

http://www.ncbi.nlm.nih.gov/pubmed/9610941

Cannabinoids in pain and inflammation.

“Cannabinoids exhibit medicinal properties including analgesic, anti-inflammatory and immunosuppressive properties. This paper reviews some of the recent findings in the study of cannabinoids in pain and inflammation. Some of the effects of cannabinoids are receptor mediated and others are receptor independent. Endocannabinoids naturally reduce pain and are cerebroprotective. Natural and synthetic cannabinoids have the potential to reduce nociception, reverse the development of allodynia and hyperalgesia, reduce inflammation and inflammatory pain and protect from secondary tissue damage in traumatic head injury.”

http://www.ncbi.nlm.nih.gov/pubmed/15265314

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

Peripheral interactions between cannabinoid and opioid receptor agonists in a model of inflammatory mechanical hyperalgesia.

“Activation of opioid and cannabinoid receptors expressed in nociceptors induces effective antihyperalgesia.

In this study, we examined whether combinations of opioid and cannabinoid receptor agonists directed at the injured site would enhance therapeutic effectiveness.

Our findings showed that MOR and CB1 agonists directed at the inflamed site effectively attenuate mechanical hyperalgesia when administered individually, but exert opposing effects when administered together.

The antagonistic interactions between the two classes of drugs at the inflamed site suggest distinct mechanisms unique to peripheral nociceptors or inflamed tissue, and therefore require further studies to investigate whether the therapeutic utility of the combined drug treatments in chronic pain conditions can be optimized.”

http://www.ncbi.nlm.nih.gov/pubmed/27450703

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/