am-1241 and arachidonyl-2-chloroethylamide

We evaluated the pharmacology of spinal selective cannabinoid (CB) receptor agonists and a cyclooxygenase-2 (COX-2) inhibitor on bone tumor pain. MRMT-1 tumor cells were injected into the tibia of female Sprague-Dawley rats. MRMT-1 tumor cells produced a bone tumor confirmed by radiologic and histological findings. Intrathecal CB1 (ACEA) and CB2 receptor (AM 1241) agonists and a COX-2 inhibitor (DuP 697) dose-dependently increased the withdrawal threshold. The calculated ED50 (nmol/l) values for ACEA, AM 1241 and DuP 697 were 0.007, 2.3 and 76.1, respectively. Reverse transcriptase polymerase chain reaction and Western blot showed that COX-2 mRNA and protein, but not CB1 or CB2 receptor, were increased in the spinal cords of rats with bone tumors. Spinal CB1 receptor and CB2 receptor agonists and COX-2 inhibitor may be useful in the management of bone tumor pain. Furthermore, CB2 receptor agonist may be more potent than CB1 receptor agonist and COX-2 inhibitor.

Topics: Animals; Arachidonic Acids; Bone Neoplasms; Cannabinoid Receptor Agonists; Cannabinoids; Cell Line, Tumor; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Female; Hyperalgesia; Pain; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; RNA, Messenger; Spinal Cord; Thiophenes; Tibia

We investigated the effects of cannabinoid receptor agonists on (1) oral cancer cell viability in vitro and (2) oral cancer pain and tumor growth in a mouse cancer model. We utilized immunohistochemistry and Western blot to show that human oral cancer cells express CBr1 and CBr2. When treated with WIN55,212-2 (non-selective), ACEA (CBr1-selective) or AM1241 (CBr2-selective) agonists in vitro, oral cancer cell proliferation was significantly attenuated in a dose-dependent manner. In vivo, systemic administration (0.013M) of WIN55,212-2, ACEA, or AM1241 significantly attenuated cancer-induced mechanical allodynia. Tumor growth was also significantly attenuated with systemic AM1241 administration. Our findings suggest a direct role for cannabinoid mechanisms in oral cancer pain and proliferation. The systemic administration of cannabinoid receptor agonists may have important therapeutic implications wherein cannabinoid receptor agonists may reduce morbidity and mortality of oral cancer.

Topics: Analgesics; Animals; Arachidonic Acids; Benzoxazines; Blotting, Western; Cannabinoids; Cell Line, Tumor; Cell Proliferation; Disease Models, Animal; Female; Fluorescent Antibody Technique; Humans; Hyperalgesia; Immunohistochemistry; Mice; Mice, Nude; Morpholines; Mouth Neoplasms; Naphthalenes; Pain; Receptors, Cannabinoid

Cannabinoid receptors CB1 and CB2 are expressed in the liver, but their regulation in fatty hepatocytes is poorly documented. The aim of this study was to investigate the effects of selective CB1 or CB2 agonists on the expression of key regulators of lipid metabolism.. We used an in vitro model of fatty liver by treating immortalized human hepatocytes and HepG2 cells with oleic acid and the selective agonists arachidonyl-2-chloroethylamide (ACEA) (CB1, 12 nM) and (2-iodo-5-nitrophenyl)-[1-(1-methylpiperidin-2-ylmethyl)-1H-indol-3-yl]-methanone (AM1241) (CB2, 16 nM). The quantity of intracellular lipids was assessed using Oil-Red-O and a biochemical triglyceride assay. The expression of several proteins regulating endocannabinoid signalling and lipid metabolism was quantified by real-time polymerase chain reaction and by Western blot.. Both CB1 and CB2 agonists dose-dependently increased the degree of steatosis of oleic acid-treated fatty hepatocytes. Cannabinoid receptors were downregulated in the presence of steatosis, and treatment with a CB2 agonist increased the expression of CB1. Carnitine palmitoyltransferase 1 was significantly overexpressed and sterol response element-binding protein (SREBP)-1c, fatty acid synthase and lecithin-cholesterol acetyltransferase (LCAT) were downregulated in fatty immortalized human hepatocytes. Treatment with the CB agonists ACEA and AM1241 partially reversed these changes, except for SREBP-1c. CB2, but not CB1, agonism decreased the expression of apolipoprotein B. In HepG2 cells, only LCAT resulted increased after treatment with CB agonists.. Not only CB1 but also CB2 participated in the regulation of lipid metabolism in human-derived immortalized hepatocytes by regulating the expression of key enzymes of lipid synthesis and transport.

Topics: Apolipoproteins B; Arachidonic Acids; Biological Transport; Blotting, Western; Cannabinoids; Carnitine O-Palmitoyltransferase; Dose-Response Relationship, Drug; Fatty Acid Synthase, Type I; Fatty Liver; Gene Expression Regulation; Hep G2 Cells; Hepatocytes; Humans; Lipid Metabolism; Non-alcoholic Fatty Liver Disease; Oleic Acid; Phosphatidylcholine-Sterol O-Acyltransferase; Receptor Cross-Talk; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Reverse Transcriptase Polymerase Chain Reaction; Sterol Regulatory Element Binding Protein 1; Triglycerides; Up-Regulation

Topics: Animals; Apolipoproteins B; Arachidonic Acids; Biological Transport; Cannabinoids; Carnitine O-Palmitoyltransferase; Fatty Acid Synthase, Type I; Fatty Liver; Gene Expression Regulation; Hepatocytes; Humans; Lipid Metabolism; Non-alcoholic Fatty Liver Disease; Phosphatidylcholine-Sterol O-Acyltransferase; Receptor Cross-Talk; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Sterol Regulatory Element Binding Protein 1; Up-Regulation

Effects of locally administered agonists and antagonists for cannabinoid CB(1) and CB(2) receptors on mechanical and thermal hypersensitivity were compared after the establishment of chronic inflammation.. Carrageenan was administered unilaterally to the rat hindpaw on day 1. Prophylactic efficacy of locally administered CB(1)- and CB(2)-selective agonists -arachidonyl-2-chloroethylamide (ACEA) and (R,S)-(2-iodo-5-nitro-phenyl)-[l-(l-methyl-piperidin-2-ylmethyl)-lH-ubdik-3-yl]-methanone ((R,S)-AM1241), respectively- on mechanical and thermal hypersensitivity were compared on day 2. Pharmacological specificity was evaluated using locally administered CB(1) and CB(2)-selective antagonists -N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamidehydrochloride (SR141716A) and N-[(1S)-endo-1,3,3-trimethyl bicycle [2.2.1] heptan-2-yl]-5-(4-chloro-3-methylphenyl)-1-(4-methylbenzyl)-pyrazole-3-carboxamide (SR144528), respectively.. Administration of either ACEA or AM1241 to the inflamed but not noninflamed paw suppressed the maintenance of carrageenan-evoked mechanical hyperalgesia and tactile allodynia and attenuated thermal hyperalgesia. The ACEA-induced suppression of mechanical and thermal hypersensitivity was blocked by local injection of SR141716A but not SR144528. AM1241 suppressed mechanical hypersensitivity with the reverse pharmacological specificity. The AM1241-induced suppression of thermal hyperalgesia was blocked by SR144528 and to a lesser extent by SR14176A. Co-administration of ACEA with AM1241 in the inflamed paw increased the magnitude but not the duration of thermal antihyperalgesia compared to intraplantar administration of either agonist alone.. Cannabinoids act locally through distinct CB(1) and CB(2) mechanisms to suppress mechanical hypersensitivity after the establishment of chronic inflammation, at doses that produced modest changes in thermal hyperalgesia. Additive antihyperalgesic effects were observed following prophylactic co-administration of the CB(1)- and CB(2)-selective agonists. Our results suggest that peripheral cannabinoid antihyperalgesic actions may be exploited for treatment of inflammatory pain states.

Topics: Animals; Arachidonic Acids; Cannabinoids; Carrageenan; Chronic Disease; Drug Synergism; Hot Temperature; Hyperalgesia; Inflammation; Male; Pain; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Touch