Cannabinoid CB2 receptor-mediated anti-nociception in models of acute and chronic pain.

Abstract

“The endocannabinoid system consists of cannabinoid CB(1) and CB(2) receptors, endogenous ligands and their synthesising/metabolising enzymes. Cannabinoid receptors are present at key sites involved in the relay and modulation of nociceptive information. The analgesic effects of cannabinoids have been well documented. The usefulness of nonselective cannabinoid agonists can, however, be limited by psychoactive side effects associated with activation of CB(1) receptors. Following the recent evidence for CB(2) receptors existing in the nervous system and reports of their up-regulation in chronic pain states and neurodegenerative diseases, much research is now aimed at shedding light on the role of the CB(2) receptor in human disease. Recent studies have demonstrated anti-nociceptive effects of selective CB(2) receptor agonists in animal models of pain in the absence of CNS side effects. This review focuses on the analgesic potential of CB(2) receptor agonists for inflammatory, post-operative and neuropathic pain states and discusses their possible sites and mechanisms of action”

http://www.ncbi.nlm.nih.gov/pubmed/17952647

Endocannabinoids and Liver Disease. I. Endocannabinoids and their receptors in the liver

  “The medicinal properties of cannabis (Cannabis sativa, marijuana) have been known for millennia, as shown by reports from China and India underscoring its analgesic, antiemetic, and appetite-stimulating properties. During the 19th century, the prescription of cannabis gained popularity for a variety of conditions ranging from epilepsy to rheumatism and abdominal symptoms. Concerns about abuse led to discontinuation of therapeutic use in the 1940s. The characterization of marijuana-derived bioactive molecules began during the early 20th century with the identification of several hydrophobic compounds and culminated in 1964 with the isolation of Δ9-tetrahydrocannabinol (THC), the main psychoactive constituent of the plant. Subsequent studies identified over 60 other phytocannabinoids and allowed the synthesis of active analogs with varying potencies. This step was critical in the identification of the endocannabinoid system, comprising specific cannabinoid binding sites (CB1 and CB2), their endogenous ligands (endocannabinoids), and synthetic and degradative pathways.”

“Cannabinoid receptors (CB1 and CB2) and their endogenous ligands (endocannabinoids) have recently emerged as novel mediators of liver diseases. Endogenous activation of CB1 receptors promotes nonalcoholic fatty liver disease (NAFLD) and progression of liver fibrosis associated with chronic liver injury; in addition, CB1 receptors contribute to the pathogenesis of portal hypertension and cirrhotic cardiomyopathy. CB2 receptor-dependent effects are also increasingly characterized, including antifibrogenic effects and regulation of liver inflammation during ischemia-reperfusion and NAFLD. It is likely that the next few years will allow us to delineate whether molecules targeting CB1 and CB2 receptors are useful therapeutic agents for the treatment of chronic liver diseases.”

http://ajpgi.physiology.org/content/294/1/G9.long

Evaluation of oral cannabinoid-containing medications for the management of interferon and ribavirin-induced anorexia, nausea and weight loss in patients treated for chronic hepatitis C virus

  “The systemic and cognitive side effects of hepatitis C virus (HCV) therapy may be incapacitating, necessitating dose reductions or abandonment of therapy. Oral cannabinoid-containing medications (OCs) ameliorate chemotherapy-induced nausea and vomiting, as well as AIDS wasting syndrome. The efficacy of OCs in managing HCV treatment-related side effects is unknown.”

 

“Although formal studies are lacking, there is anecdotal evidence that cannabis may be beneficial by alleviating common side effects associated with interferon-ribavirin, including anorexia, nausea, weight loss and insomnia. Despite the potential benefits of cannabis, concerns related to the long-term medical complications of inhaled cannabis use and the inability to legally obtain this product limit the use of it as a therapeutic intervention.”

“Oral cannabinoid-containing medications (OCs) have multiple potential therapeutic uses due to their analgesic, antiemetic, anticonvulsant, bronchodilatory and anti-inflammatory effects. They have been shown in clinical trials to ameliorate chemotherapy-induced nausea, to benefit those with AIDS wasting syndrome and to reduce spasticity in multiple sclerosis patients.”

“CONCLUSIONS:

The present retrospective cohort analysis found that OC use is often effective in managing HCV treatment-related symptoms that contribute to weight loss, and may stabilize weight decline once initiated.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2662895/

A molecular basis of the therapeutic and psychoactive properties of cannabis (delta9-tetrahydrocannabinol).

Abstract

“All of the therapeutic properties of marihuana (analgesic, antiemetic, appetite stimulant, antiglaucoma) have been duplicated by the tetrahydrocannabinol (THC) molecule or its synthetic derivatives. Today, the molecular mechanisms of action of these compounds have led to a general understanding of the pharmacological effects of marihuana and of its therapeutic properties. These mechanisms involve the specific binding of THC to the 7-transmembrane (7TM) domain G protein-linked receptor, a molecular switch which regulates signal transduction in the cell membrane. The natural ligand of the 7TM receptor is an eicosanoid, arachidonylethanolamide (AEA), generated in the membrane and derived from arachidonic acid. THC acts as a substitute ligand to the 7TM receptor site of AEA. THC would deregulate the physiological function of the 7TM receptor and of its ligand AEA. As a result, the therapeutic effects of the drug may not be separated from its adverse psychoactive and cardiovascular effects. The binding of THC to the 7TM receptor site of AEA induces allosteric changes in the receptor sites of neurotransmitter and opiates resulting in variable interactions and pharmacological responses. The pharmacokinetics of THC with its prolonged storage in fat and its slow release result in variable and delayed pharmacological response, which precludes precise dosing to achieve timely therapeutic effects. The experimental use of THC and of its synthetic analogues, agonists, and antagonists has provided novel information in the nature of molecular signaling in the cell membrane. As a result, the relationships between allosteric receptor responsiveness, molecular configuration of proteins, and physiological regulation of cellular and organ function may be further investigated.”

http://www.ncbi.nlm.nih.gov/pubmed/12188105

The cannabinoid acids: nonpsychoactive derivatives with therapeutic potential.

Abstract

   “The discovery of carboxylic acid metabolites of the cannabinoids (CBs) dates back more than three decades. Their lack of psychotropic activity was noted early on, and this resulted in a total absence of further research on their possible role in the actions of the CBs. More recent studies have revealed that the acids possess both analgesic and anti-inflammatory properties and may contribute to the actions of the parent drug. A synthetic analog showed similar actions at considerably lower doses. In this review, a brief survey of the extensive literature on metabolism of delta 9-tetrahydrocannabinol to the acids is presented, while more emphasis is given to the recent findings on the biological actions of this class of CBs. A possible mechanism involving effects on eicosanoids for some of these actions is also suggested. Finally, an analogy with a putative metabolite of anandamide, an endogenous CB, is discussed.”

http://www.ncbi.nlm.nih.gov/pubmed/10341359

Activation and Binding of Peroxisome Proliferator-Activated Receptor γ by Synthetic Cannabinoid Ajulemic Acid

   “Ajulemic acid (AJA) is a synthetic analog of the tetrahydrocannabinol (THC) metabolite THC-11-oic acid; THC is a major active ingredient of the drug marijuana derived from the plant cannabis. AJA has potent analgesic and anti-inflammatory activity without the psychotropic action of THC. Unlike the nonsteroidal anti-inflammatory drugs, AJA is not ulcerogenic at therapeutic doses, making it a promising anti-inflammatory drug. However, the mechanism of AJA action remains unknown. Here we report that AJA binds directly and specifically to the peroxisome proliferator-activated receptor γ (PPARγ), a pharmacologically important member of the nuclear receptor superfamily. Functional assay indicates that AJA activates the transcriptional activity of both human and mouse PPARγ at pharmacological concentrations. Activation of PPARγ by AJA requires the AF-2 helix of the receptor, suggesting that AJA activates PPARγ through the ligand-dependent AF-2 function. AJA binding consistently enables PPARγ to recruit nuclear receptor coactivators. In addition, we show that AJA inhibits interleukin-8 promoter activity in a PPARγ-dependent manner, suggesting a link between the anti-inflammatory action of AJA and the activation of PPARγ. Finally, we find that AJA treatment induces differentiation of 3T3 L1 fibroblasts into adipocytes, a process mediated by PPARγ. Together, these data indicate that PPARγ may be a molecular target for AJA, providing a potential mechanism for the anti-inflammatory action of AJA, and possibly other cannabinoids. These studies also implicate other potential therapeutic actions of AJA through PPARγ activation in multiple signaling pathways.”

“The mood-altering drug marijuana derived from the hemp plant Cannabis sativa contains a group of biosynthetically related substances known collectively as cannabinoids. Tetrahydrocannabinol (THC), one of the major cannabinoids in marijuana, has potent analgesic and anti-inflammatory activities, but it also exhibits psychotropic effects, which limit its clinical application. Considerable effort has been expended toward the goal of creating nonpsychotropic cannabinoid derivatives that retain therapeutic actions but are free of psychotropic activity. A useful template for this search is the THC metabolite THC-11-oic acid…”

http://molpharm.aspetjournals.org/content/63/5/983.long

Ajulemic Acid, a Synthetic Nonpsychoactive Cannabinoid Acid, Bound to the Ligand Binding Domain of the Human Peroxisome Proliferator-activated Receptor γ*

  “Ajulemic acid (AJA) is a synthetic analog of THC-11-oic acid, a metabolite of tetrahydrocannabinol (THC), the major active ingredient of the recreational drug marijuana derived from the plant Cannabis sativa. AJA has potent analgesic and anti-inflammatory activity in vivo, but without the psychotropic action of THC. However, its precise mechanism of action remains unknown. Biochemical studies indicate that AJA binds directly and selectively to the isotype γ of the peroxisome proliferator-activated receptor (PPARγ) suggesting that this may be a pharmacologically relevant receptor for this compound and a potential target for drug development in the treatment of pain and inflammation. Here, we report the crystal structure of the ligand binding domain of the γ isotype of human PPAR in complex with ajulemic acid, determined at 2.8-Å resolution. Our results show a binding mode that is compatible with other known partial agonists of PPAR, explaining their moderate activation of the receptor, as well as the structural basis for isotype selectivity, as observed previously in vitro. The structure also provides clues to the understanding of partial agonism itself, suggesting a rational approach to the design of molecules capable of activating the receptor at levels that avoid undesirable side effects.”

“AJA (also known as CT-3, IP-751, or 1′,1′-dimethylheptyl-Δ8-tetrahydrocannabinol-11-oic acid) was originally designed based on observations of the metabolic transformations of THC using the metabolite THC-11-oic acid as a template. AJA suppresses neuropathic pain in humans and prevents joint tissue injury in rat models of inflammatory arthritis. In all cases, these effects are observed without producing the motor side effects associated with THC.”

“In summary, our results show that AJA, as well as other THC analogs, in presenting specific binding together with minimal toxicity and good bioavailability may provide useful novel templates for rational drug design aimed at PPARγ regulation.”

 http://www.jbc.org/content/282/25/18625.long

Ajulemic acid (IP-751): Synthesis, proof of principle, toxicity studies, and clinical trials

Abstract

  “Ajulemic acid (CT-3, IP-751, 1′,1′-dimethylheptyl-Delta8-tetrahydrocannabinol-11-oic acid) (AJA) has a cannabinoid-derived structure; however, there is no evidence that it produces psychotropic actions when given at therapeutic doses. In a variety of animal assays, AJA shows efficacy in models for pain and inflammation. Furthermore, in the rat adjuvant arthritis model, it displayed a remarkable action in preventing the destruction of inflamed joints. A phase-2 human trial with chronic, neuropathic pain patients suggested that AJA could become a useful drug for treating this condition. Its low toxicity, particularly its lack of ulcerogenicity, further suggests that it will have a highly favorable therapeutic index and may replace some of the current anti-inflammatory/analgesic medications. Studies to date indicate a unique mechanism of action for AJA that may explain its lack of adverse side effects.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2751505/

Ajulemic acid (CT3): a potent analog of the acid metabolites of THC.

Abstract

“The acid metabolites of THC were discovered almost 30 years ago and were later shown to posses modest analgesic and anti-inflammatory activity in a variety of models. Ajulemic acid (CT3) is a more potent analog of THC-11-oic acid in which a dimethylheptyl side chain is substituted for the pentyl side chain of the naturally occurring metabolite. It produces analgesia in the mouse hot plate, the PPQ writhing, the formalin and the tail clip assays. In the latter, it was equipotent to morphine; however, it showed a much greater duration of action. In the paw edema, subcutaneous air pouch and rat adjuvant-induced arthritis models of inflammation; it showed significant therapeutic activity at a dose of 0.2 mg/kg p.o. In the arthritis model it greatly reduced permanent damage to joints when compared to an indomethacin control as evidenced by an improved joint score over vehicle controls and by histopathological examination. In contrast to the NSAIDs, it was totally nonulcerogenic at therapeutically relevant doses. Moreover, it does not depress respiration, exhibit dependence, induce body weight loss or cause mutagenesis. It shows none of the typical actions in models of the psychotropic actions of cannabinoids suggesting that a good separation of desirable from undesirable effects was achieved. Studies on its mechanism of action are currently underway. The data thus far suggest the existence of a novel receptor for ajulemic acid with possible downstream effects on eicosanoid production, cytokine synthesis and metalloprotease activity. There is also circumstantial evidence for a putative endogenous ajulemic acid, namely, arachidonylglycine.”

http://www.ncbi.nlm.nih.gov/pubmed/10903396

1′,1′-Dimethylheptyl-Δ-8-tetrahydrocannabinol-11-oic Acid: A Novel, Orally Effective Cannabinoid with Analgesic and Anti-inflammatory Properties

  “1′,1′-Dimethylheptyl-Δ-8-tetrahydrocannabinol-11-oic acid (CT-3) is a novel cannabinoid that is under development by Atlantic Pharmaceuticals as an anti-inflammatory and analgesic drug. The objective of the study was to investigate the effects of CT-3 on overt symptom complex (Irwin’s test), nociception, gastrointestinal (GI) ulceration, and pharmacological availability after intragastric (i.g.) and intraperitoneal (i.p.) administration… .The evidence indicates that CT-3 exhibits a large dissociation between its anti-inflammatory/analgesic effects and its ulcerogenic actions. CT-3 warrants clinical development as a novel anti-inflammatory and analgesic drug.”

“1′,1′-Dimethylheptyl-Δ-8-tetrahydrocannabinol-11-oic acid (CT-3) is a novel cannabinoid with analgesic and anti-inflammatory activities. CT-3 is chemically similar to Δ-9-tetrahydrocannabinol (THC, dronabilone) and nabilone.”

“Analgesia is one of the most profound effects of THC in most species after its parenteral administration, and THC had shown equivalent potency to morphine in rats and mice in a variety of analgesic tests, including the tail-flick latency measurements. Several synthetic cannabinoids have also shown analgesic activities in animal models selective for detecting opiate analgesics.”

“The analgesic action of CT-3 is well confirmed in rats and in mice. Available evidence indicates that CT-3 exhibits two distinct pharmacological properties: an anti-inflammatory property occurring at a very low dose (ED50 = ∼0.1 mg/kg i.g.; and an analgesic property occurring at a higher dose (ED50 = ∼5 mg/kg i.g. and i.p.). The present results indicate that CT-3 is an orally effective analgesic drug, and acceptable pharmaceutical formulation of CT-3 would not require the adjuvant use of permeability enhancers to promote its bioavailability. CT-3 clearly warrants clinical development as an analgesic and anti-inflammatory drug.”

http://jpet.aspetjournals.org/content/291/1/31.long