The peripheral cannabinoid receptor: adenylate cyclase inhibition and G protein coupling.

“Two cannabinoid receptors, designated neuronal (or CB1) and peripheral (or CB2), have recently been cloned. Activation of CB1 receptors leads to inhibition of adenylate cyclase and N-type voltage-dependent Ca2+ channels.

Here we show, using a CB2 transfected Chinese hamster ovary cell line, that this receptor binds a variety of tricyclic cannabinoid ligands as well as the endogenous ligand anandamide.

Activation of the CB2 receptor by various tricyclic cannabinoids inhibits adenylate cyclase activity and this inhibition is pertussis toxin sensitive indicating that this receptor is coupled to the Gi/G(o) GTP-binding proteins…

These results characterize the CB2 receptor as a functional and distinctive member of the cannabinoid receptor family.”

http://www.ncbi.nlm.nih.gov/pubmed/7498464

 

Anandamide, a brain endogenous compound, interacts specifically with cannabinoid receptors and inhibits adenylate cyclase.

“A putative endogenous cannabinoid ligand, arachidonylethanolamide (termed “anandamide”), was isolated recently from porcine brain.

Here we demonstrate that this compound is a specific cannabinoid agonist and exerts its action directly via the cannabinoid receptors.

Anandamide specifically binds to membranes from cells transiently (COS) or stably (Chinese hamster ovary) transfected with an expression plasmid carrying the cannabinoid receptor DNA but not to membranes from control nontransfected cells.

Moreover, anandamide inhibited the forskolin-stimulated adenylate cyclase in the transfected cells and in cells that naturally express cannabinoid receptors (N18TG2 neuroblastoma) but not in control nontransfected cells. As with exogenous cannabinoids…

These data indicate that anandamide is an endogenous agonist that may serve as a genuine neurotransmitter for the cannabinoid receptor.”

http://www.ncbi.nlm.nih.gov/pubmed/8515284

The anti-hyperalgesic actions of the cannabinoid anandamide and the putative CB2 receptor agonist palmitoylethanolamide in visceral and somatic inflammatory pain.

“The therapeutic effects of the cannabinoid anandamide and the putative CB2 agonist palmitoylethanolamide were tested in a model of persistent visceral pain (turpentine inflammation of the urinary bladder)…

The results confirm the analgesic potential of endogenous ligands at cannabinoid receptor sites.

The anti-nociceptive effect of the putative CB2 receptor agonist, palmitoylethanolamide, is particularly interesting since it is believed to be a peripherally mediated effect.

This observation might be exploited to separate central psychotropic effects from peripheral analgesic actions of the cannabinoids, under inflammatory conditions.”

http://www.ncbi.nlm.nih.gov/pubmed/9696473

Targeting the Endocannabinoid System for Neuroprotection: A 19F-NMR Study of a Selective FAAH Inhibitor Binding with an Anandamide Carrier Protein, HSA.

“Fatty acid amide hydrolase (FAAH), the enzyme involved in the inactivation of the endocannabinoid anandamide (AEA), is being considered as a therapeutic target for analgesia and neuroprotection…
The endocannabinoid system has been implicated as a therapeutic target for analgesia, anti-emesis, and neuroprotection… These findings provide a potential new therapeutic modality for neuroprotection through dual inhibition of FAAH and anandamide carrier proteins…”

Figure 1

Intense exercise increases circulating endocannabinoid and BDNF levels in humans–possible implications for reward and depression.

“The endocannabinoid system is known to have positive effects on depression partly through its actions on neurotrophins, such as Brain-Derived Neurotrophic Factor (BDNF). As BDNF is also considered the major candidate molecule for exercise-induced brain plasticity, we hypothesized that the endocannabinoid system represents a crucial signaling system mediating the beneficial antidepressant effects of exercise…

These findings provide evidence in humans that acute exercise represents a physiological stressor able to increase peripheral levels of AEA and that BDNF might be a mechanism by which AEA influences the neuroplastic and antidepressant effects of exercise.”

http://www.ncbi.nlm.nih.gov/pubmed/22029953

“Neuroplasticity – exercise-induced response of peripheral brain-derived neurotrophic factor: a systematic review of experimental studies in human subjects. Exercise is known to induce a cascade of molecular and cellular processes that support brain plasticity. Brain-derived neurotrophic factor (BDNF) is an essential neurotrophin that is also intimately connected with central and peripheral molecular processes of energy metabolism and homeostasis, and could play a crucial role in these induced mechanisms… We can only speculate which central regions and peripheral sources in particular circulating BDNF originates from,…” http://www.ncbi.nlm.nih.gov/pubmed/20726622

“Preliminary evidence of cannabinoid effects on brain-derived neurotrophic factor (BDNF) levels in humans… cannabinoids modulate brain-derived neurotrophic factor (BDNF)… Delta(9)-THC increased serum BDNF levels…” http://www.ncbi.nlm.nih.gov/pubmed/18807247

“Antidepressant-like effects of Δ⁹-tetrahydrocannabinol…” http://www.ncbi.nlm.nih.gov/pubmed/22634064

“Antidepressant-like effects of cannabidiol… CBD treatment did not change hippocampal BDNF levels… CBD induces antidepressant-like effects…” http://www.ncbi.nlm.nih.gov/pubmed/20002102

Endocannabinoids as biomarkers of human reproduction.

“The search for suitable biomarkers of pregnancy outcome is a challenging issue in human reproduction, aimed at identifying molecules with predictive significance of the reproductive potential of male and female gametes.

Among the various candidates, endocannabinoids (eCBs), and in particular anandamide (AEA), represent potential biomarkers of human fertility disturbances…

Based on the available data, we suggest that the AEA tone has the potential to be exploited as a novel diagnostic biomarker of infertility,”

http://www.ncbi.nlm.nih.gov/pubmed/24516083

The endocannabinoid anandamide inhibits voltage-gated sodium channels nav1.2, nav1.6, nav1.7, and nav1.8 in Xenopus oocytes.

“Anandamide is an endocannabinoid that regulates multiple physiological functions by pharmacological actions, in a manner similar to marijuana. Recently, much attention has been paid to the analgesic effect of endocannabinoids in terms of identifying new pharmacotherapies for refractory pain management, but the mechanisms of the analgesic effects of anandamide are still obscure…

Anandamide inhibited the function of α subunits in neuronal sodium channels Nav1.2, Nav1.6, Nav1.7, and Nav1.8.

These results help clarify the mechanisms of the analgesic effects of anandamide.”

http://www.ncbi.nlm.nih.gov/pubmed/24557103

Targeting the cannabinoid system for pain relief?

“Marijuana has been used to relieve pain for centuries, but its analgesic mechanism has only been understood during the past two decades. It is mainly mediated by its constituents, cannabinoids, through activating central cannabinoid 1 (CB1) receptors, as well as peripheral CB1 and CB2receptors.

CB2-selective agonists have the benefit of lacking CB1 receptor-mediated CNS side effects. Anandamide and 2-arachidonoylglycerol (2-AG) are two intensively studied endogenous lipid ligands of cannabinoid receptors, termed endocannabinoids, which are synthesized on demand and rapidly degraded…

In addition to the antinociceptive properties of  exogenous cannabinoids and endocannabinoids, involving their biosynthesis and degradation processes, we also review recent studies that revealed a novel analgesic mechanism, involving 2-AG in the periaqueductal gray (PAG), a midbrain region for initiating descending pain inhibition…”

http://www.ncbi.nlm.nih.gov/pubmed/24529672

Anandamide in primary sensory neurons: too much of a good thing?

“The quest for possible targets for the development of novel analgesics has identified the activation of the cannabinoid type 1 (CB1) receptor outside the CNS as a potential means of providing relief from persistent pain, which currently constitutes an unmet medical need.

Increasing tissue levels of the CB1 receptor endogenous ligand N-arachidonoylethanolamine (anandamide), by inhibiting anandamide degradation through blocking the anandamide-hydrolysing enzyme fatty acid amide hydrolase, has been suggested to be used to activate the CB1 receptor.

However, recent clinical trials revealed that this approach does not deliver the expected relief from pain. Here, we discuss one of the possible reasons, the activation of the transient receptor potential vanilloid type 1 ion channel (TRPV1) on nociceptive primary sensory neurons (PSNs) by anandamide, which may compromise the beneficial effects of increased tissue levels of anandamide.

We conclude that better design such as concomitant blocking of anandamide hydrolysis and anandamide uptake into PSNs, to inhibit TRPV1 activation, could overcome these problems.”

http://www.ncbi.nlm.nih.gov/pubmed/24494681

5-Lipoxygenase and anandamide hydrolase (FAAH) mediate the antitumor activity of cannabidiol, a non-psychoactive cannabinoid.

“It has been recently reported that cannabidiol (CBD), a non-psychoactive cannabinoid, is able to kill glioma cells, both in vivo and in vitro, independently of cannabinoid receptor stimulation.

…the present investigation indicates that CBD exerts its antitumoral effects through modulation of the LOX pathway and of the endocannabinoid system…”

http://www.ncbi.nlm.nih.gov/pubmed/18028339