sq-23377 and anandamide

Topics: Animals; Arachidonic Acids; Astrocytes; Brain; Calcium; Calcium Channels; Cells, Cultured; Endocannabinoids; Ionomycin; Membrane Lipids; Neurons; Phosphatidylethanolamines; Phosphoric Diester Hydrolases; Polyunsaturated Alkamides; Rats; Receptors, Cannabinoid; Receptors, Drug; Veratridine

Endocannabinoids and related N-acylethanolamines (NAEs) are involved in regulation of gut function, but relatively little is known as to whether inflammatory cytokines such as IFNγ affect their levels. We have investigated this in vitro using cultures of T84 colon cancer cells.. T84 cells, when cultured in monolayers, differentiate to form adult colonic crypt-like cells with excellent permeability barrier properties. The integrity of the permeability barrier in these monolayers was measured using transepithelial electrical resistance (TEER). NAE levels were determined by ultra-performance liquid chromatography-tandem mass spectrometric analysis. Expression of the enzymes involved in NAE and 2-arachidonoylglycerol (2-AG) turnover were assessed with qPCR.. IFNγ treatment for 8 or 24 h increased levels of both endocannabinoids (anandamide and 2-AG) and the related NAEs. The treatment did not affect the rate of hydrolysis of either anandamide or palmitoylethanolamide by intact cells, and in both cases, fatty acid amide hydrolase (FAAH) rather than NAE-hydrolysing acid amidase (NAAA) was mainly responsible for the hydrolysis of these NAEs. IFNγ treatment reduced the TEER of the cells in a manner that was not prevented by inhibition of either FAAH or NAAA but was partially reversed by apical administration of the NAE palmitoylethanolamide.. IFNγ treatment mobilized endocannabinoid and related NAE levels in T84 cells. However, blockade of anandamide or NAE hydrolysis was insufficient to negate the deleterious effects of this cytokine upon the permeability barrier of the cell monolayers.

Topics: Amides; Arachidonic Acids; Cell Culture Techniques; Cell Line, Tumor; Chromatography, High Pressure Liquid; Colonic Neoplasms; Endocannabinoids; Ethanolamines; Glycerides; Humans; Interferon-gamma; Ionomycin; Palmitic Acids; Polyunsaturated Alkamides

Increased endocannabinoid tonus by dual-action fatty acid amide hydrolase (FAAH) and substrate selective cyclooxygenase (COX-2) inhibitors is a promising approach for pain-relief. One such compound with this profile is 2-(2-fluorobiphenyl-4-yl)-N-(3-methylpyridin-2-yl)propanamide (Flu-AM1). These activities are shown by Flu-AM1 racemate, but it is not known whether its two single enantiomers behave differently, as is the case towards COX-2 for the parent flurbiprofen enantiomers. Further, the effects of the compound upon COX-2-derived lipids in intact cells are not known.. COX inhibition was determined using an oxygraphic method with arachidonic acid and 2-arachidonoylglycerol (2-AG) as substrates. FAAH was assayed in mouse brain homogenates using anandamide (AEA) as substrate. Lipidomic analysis was conducted in unstimulated and lipopolysaccharide + interferon γ- stimulated RAW 264.7 macrophage cells. Both enantiomers inhibited COX-2 in a substrate-selective and time-dependent manner, with IC50 values in the absence of a preincubation phase of: (R)-Flu-AM1, COX-1 (arachidonic acid) 6 μM; COX-2 (arachidonic acid) 20 μM; COX-2 (2-AG) 1 μM; (S)-Flu-AM1, COX-1 (arachidonic acid) 3 μM; COX-2 (arachidonic acid) 10 μM; COX-2 (2-AG) 0.7 μM. The compounds showed no enantiomeric selectivity in their FAAH inhibitory properties. (R)-Flu-AM1 (10 μM) greatly inhibited the production of prostaglandin D2 and E2 in both unstimulated and lipopolysaccharide + interferon γ- stimulated RAW 264.7 macrophage cells. Levels of 2-AG were not affected either by (R)-Flu-AM1 or by 10 μM flurbiprofen, either alone or in combination with the FAAH inhibitor URB597 (1 μM).. Both enantiomers of Flu-AM1 are more potent inhibitors of 2-AG compared to arachidonic acid oxygenation by COX-2. Inhibition of COX in lipopolysaccharide + interferon γ- stimulated RAW 264.7 cells is insufficient to affect 2-AG levels despite the large induction of COX-2 produced by this treatment.

Topics: Amides; Amidohydrolases; Animals; Arachidonic Acid; Arachidonic Acids; Benzamides; Brain; Carbamates; Cyclooxygenase 1; Cyclooxygenase 2; Cyclooxygenase Inhibitors; Endocannabinoids; Flurbiprofen; Humans; Hydrolysis; Interferon-gamma; Ionomycin; Isoenzymes; Lipid Metabolism; Lipopolysaccharides; Male; Mice; Polyunsaturated Alkamides; Prostaglandins; RAW 264.7 Cells; Stereoisomerism

The mechanisms of endogenous cannabinoid biosynthesis are not completely understood. We hypothesized that anandamide could be recycled by the cell to form new endocannabinoid molecules and released into the extracellular space. We determined that new endocannabinoids derived from exogenous anandamide or arachidonic acid were synthesized and released from RBL-2H3 cells in response to ionomycin. Treatment of RBL-2H3 cells with nystatin and progesterone, agents that disrupt organization of lipid raft/caveolae, resulted in the attenuation of anandamide and 2-arachidonyl glycerol synthesis and/or release in response to stimulation with ionomycin suggesting a role for these membrane microdomains in endocannabinoid biosynthesis. Furthermore, anandamide synthesis may be independent of N-acyl phosphatidylethanolamine phospholipase D as expression of the enzyme was not detected in RBL-2H3 cells. We also established that extracellular calcium is necessary for endocannabinoid biosynthesis because release of intracellular calcium stores alone does not promote endocannabinoid biosynthesis. Next, we examined the role of calcium as a 'switch' to activate the synthesis of anandamide and simultaneously reduce uptake. Indeed, [(3)H] anandamide uptake was reduced in the presence of calcium. Our findings suggest a mechanism indicative of calcium-modulated activation of anandamide synthesis and simultaneous termination of uptake.

Topics: Animals; Arachidonic Acids; Biological Transport; Calcium; Caveolae; Cell Line, Transformed; Chromatography, High Pressure Liquid; Dose-Response Relationship, Drug; Endocannabinoids; Enzyme Inhibitors; Glycerides; Ionomycin; Ionophores; Lactones; Nystatin; Phospholipase D; Polyunsaturated Alkamides; Progesterone; Progestins; Rats; Thapsigargin; Time Factors; Tritium

Cannabinoids and endocannabinoids negatively influence sperm functions. These substances have been demonstrated in many mammalian tissues, including male and female reproductive tracts, and previous studies have shown the presence of functional receptors for cannabinoids in human sperm. The present study, by means of RT-PCR and Western blot techniques, demonstrates that human sperm express the CB(1), but not CB(2), cannabinoid receptor (CB-R) subtype located in the head and middle piece of the sperm. The activation of this receptor by anandamide reduces sperm motility and inhibits capacitation-induced acrosome reaction. Activation of the CB(1)-R did not induce any variation in sperm intracellular calcium concentrations, but produced a rapid plasma membrane hyperpolarization that was reduced by the K(+) channel blocker tetraethylammonium. The effects of anandamide on human sperm motility were dependent on the reduction of sperm mitochondrial activity as determined by rhodamine 123 fluorescence. The specificity of anandamide effects in human sperm were confirmed by the effects of the CB(1)-R antagonist SR141716. These findings provide additional evidence that human sperm express functional CB(1)-R, the activation of which negatively influences important sperm functions, and suggest a possible role for the cannabinoid system in the pathogenesis of some forms of male infertility.

Topics: Acrosome Reaction; Arachidonic Acids; Endocannabinoids; Female; Humans; Ionomycin; Male; Mitochondria; Ovum; Piperidines; Polyunsaturated Alkamides; Pyrazoles; Receptor, Cannabinoid, CB1; Rimonabant; Sperm Motility; Spermatozoa

Anandamide, an endogenous agonist of cannabinoid receptors, activates various signal transduction pathways. Anandamide also activates vanilloid VR(1) receptor, which was a nonselective cation channel with high Ca(2+) permeability and had sensitivity to capsaicin, a pungent principle in hot pepper. The effects of anandamide and capsaicin on arachidonic acid metabolism in neuronal cells have not been well established. We examined the effects of anandamide and capsaicin on arachidonic acid release in rat pheochromocytoma PC12 cells. Both agents stimulated [3H]arachidonic acid release in a concentration-dependent manner from the prelabeled PC12 cells even in the absence of extracellular CaCl(2). The effect of anandamide was neither mimicked by an agonist nor inhibited by an antagonist for cannabinoid receptors. The effects of anandamide and capsaicin were inhibited by phospholipase A(2) inhibitors, but not by an antagonist for vanilloid VR(1) receptor. In PC12 cells preincubated with anandamide or capsaicin, [3H]arachidonic acid release was marked and both agents were no more effective. Co-addition of anandamide or capsaicin synergistically enhanced [3H]arachidonic acid release by mastoparan in the absence of CaCl(2). Anandamide stimulated prostaglandin F(2alpha) formation. These findings suggest that anandamide and capsaicin stimulated arachidonic acid metabolism in cannabinoid receptors- and vanilloid VR(1) receptor-independent manner in PC12 cells. The possible mechanisms are also discussed.

Topics: Animals; Arachidonic Acid; Arachidonic Acids; Calcium Chloride; Capsaicin; Dinoprost; Dose-Response Relationship, Drug; Endocannabinoids; Enzyme Activators; Extracellular Space; Intercellular Signaling Peptides and Proteins; Ionomycin; Ionophores; PC12 Cells; Peptides; Phospholipases A; Polyunsaturated Alkamides; Rats; Receptors, Cannabinoid; Receptors, Drug; Wasp Venoms

The monoacylglycerol 2-arachidonoylglycerol (2-AG) has been recently suggested as a possible endogenous agonist at cannabinoid receptors both in brain and peripheral tissues. Here we report that a widely used model for neuronal cells, mouse N18TG2 neuroblastoma cells, which contain the CB1 cannabinoid receptor, also biosynthesize, release and degrade 2-AG. Stimulation with ionomycin (1-5 microM) of intact cells prelabelled with [3H]arachidonic acid ([3H]AA) led to the formation of high levels of a radioactive component with the same chromatographic behaviour as synthetic standards of 2-AG in TLC and HPLC analyses. The amounts of this metabolite were negligible in unstimulated cells, and greatly decreased in cells stimulated in the presence of the Ca2+-chelating agent EGTA. The purified component was further characterized as 2-AG by: (1) digestion with Rhizopus arrhizus lipase, which yielded radiolabelled AA; (2) gas chromatographic-MS analyses; and (3) TLC analyses on borate-impregnated plates. Approx. 20% of the 2-AG produced by stimulated cells was found to be released into the incubation medium when this contained 0.1% BSA. Subcellular fractions of N18TG2 cells were shown to contain enzymic activity or activities catalysing the hydrolysis of synthetic [3H]2-AG to [3H]AA. Cell homogenates were also found to convert synthetic [3H]sn-1-acyl-2-arachidonoylglycerols (AcAGs) into [3H]2-AG, suggesting that 2-AG might be derived from AcAG hydrolysis. When compared with ionomycin stimulation, treatment of cells with exogenous phospholipase C, but not with phospholipase D or A2, led to a much higher formation of 2-AG and AcAGs. However, treatment of cells with phospholipase A2 10 min before ionomycin stimulation caused a 2.5-3-fold potentiation of 2-AG and AcAG levels with respect to ionomycin alone, whereas preincubation with the phospholipase C inhibitor neomycin sulphate did not inhibit the effect of ionomycin on 2-AG and AcAG levels. These results suggest that the Ca2+-induced formation of 2-AG proceeds through the intermediacy of AcAGs but not necessarily through phospholipase C activation. By showing for the first time the existence of molecular mechanisms for the inactivation and the Ca2+-dependent biosynthesis and release of 2-AG in neuronal cells, the present paper supports the hypothesis that this cannabimimetic monoacylglycerol might be a physiological neuromodulator.

Topics: Animals; Arachidonic Acids; Calcium; Calcium Channel Blockers; Cannabinoids; Endocannabinoids; Enzyme Inhibitors; Glycerides; Hydrolysis; Ionomycin; Ionophores; Mice; Neuroblastoma; Neurons; Polyunsaturated Alkamides; Receptors, Cannabinoid; Receptors, Drug; Subcellular Fractions; Tumor Cells, Cultured

Understanding the mechanisms involved in the biogenesis of N-arachidonoylethanolamine (anandamide) and N-palmitoylethanolamine is important in view of the possible role of these lipids as endogenous cannabinoid substances. Anandamide (which activates cannabinoid CB1 receptors) and N-palmitoylethanolamine (which activates a CB2-like receptor subtype in mast cells) may both derive from cleavage of precursor phospholipid, N-acylphosphatidylethanolamine (NAPE), catalyzed by Ca(2+)-activated D-type phosphodiesterase activity. We report here that the de novo biosynthesis of NAPE is enhanced in a Ca(2+)-dependent manner when rat cortical neurons are stimulated with the Ca(2+)-ionophore ionomycin or with membrane-depolarizing agents such as veratridine and kainate. This reaction is likely to be mediated by a neuronal N-acyltransferase activity, which catalyzes the transfer of an acyl group from phosphatidylcholine to the ethanolamine moiety of phosphatidylethanolamine. In addition, we show that Ca2+-dependent NAPE biosynthesis is potentiated by agents that increase cAMP levels, including forskolin and vasoactive intestinal peptide. Our results thus indicate that NAPE levels in cortical neurons are controlled by Ca2+ ions and cAMP. Such regulatory effect may participate in maintaining a supply of cannabimimetic N-acylethanolamines during synaptic activity, and prime target neurons for release of these bioactive lipids.

Topics: Amides; Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acids; Arylamine N-Acetyltransferase; Astrocytes; Calcium; Calcium Channel Blockers; Calmodulin; Cannabinoids; Carbachol; Cyclic AMP; Endocannabinoids; Enzyme Inhibitors; Ethanolamine; Ethanolamines; Imidazoles; Ionomycin; Ionophores; Neurons; Nicotinic Agonists; Palmitic Acids; Phosphatidylethanolamines; Polyunsaturated Alkamides; Rats; Sodium Channel Agonists; Tritium; Vasoactive Intestinal Peptide; Veratridine

Anandamide (N-arachidonoyl-ethanolamine) was recently identified as a brain arachidonate derivative that binds to and activates cannabinoid receptors, yet the mechanisms underlying formation, release and inactivation of this putative messenger molecule are still unclear. Here we report that anandamide is produced in and released from cultured brain neurons in a calcium ion-dependent manner when the neurons are stimulated with membrane-depolarizing agents. Anandamide formation occurs through phosphodiesterase-mediated cleavage of a novel phospholipid precursor, N-arachidonoyl-phosphatidylethanolamine. A similar mechanism also governs the formation of a family of anandamide congeners, whose possible roles in neuronal signalling remain unknown. Our results and those of others indicate therefore that multiple biochemical pathways may participate in anandamide formation in brain tissue. The life span of extracellular anandamide is limited by a rapid and selective process of cellular uptake, which is accompanied by hydrolytic degradation to ethanolamine and arachidonate. Our results thus strongly support the proposed role of anandamide as an endogenous neuronal messenger.

Topics: Animals; Arachidonic Acids; Astrocytes; Cannabinoids; Cells, Cultured; Central Nervous System; Cerebral Cortex; Corpus Striatum; Endocannabinoids; Ionomycin; Neurons; Phosphatidylethanolamines; Polyunsaturated Alkamides; Rats; Signal Transduction

Anandamide (arachidonylethanolamide) is an endogenous cannabinoid receptor agonist in mammalian brain. Sea urchin sperm contain a high-affinity cannabinoid receptor similar to the cannabinoid receptor in mammalian brain. (-)-delta 9-Tetrahydrocannabinol (THC), the primary psychoactive cannabinoid in marihuana, reduces the fertilizing capacity of sea urchin sperm by blocking the acrosome reaction that normally is stimulated by a specific ligand in the egg's jelly coat. We now report that anandamide produces effects similar to those previously obtained with THC in Strongylocentrotus purpuratus in reducing sperm fertilizing capacity and inhibiting the egg jelly-stimulated acrosome reaction. Arachidonic acid does not inhibit the acrosome reaction under similar conditions. The adverse effects of anandamide on sperm fertilizing capacity and the acrosome reaction are reversible. The receptivity of unfertilized eggs to sperm and sperm motility are not impaired by anandamide. Under conditions where anandamide completely blocks the egg jelly-stimulated acrosome reaction, it does not inhibit the acrosome reaction artificially initiated by ionomycin, which promotes Ca2+ influx, and nigericin, which activates K+ channels in sperm. These findings provide additional evidence that the cannabinoid receptor in sperm plays a role in blocking the acrosome reaction, indicate that anandamide or a related molecule may be the natural ligand for the cannabinoid receptor in sea urchin sperm, and suggest that binding of anandamide to the cannabinoid receptor modulates stimulus-secretion-coupling in sperm by affecting an event prior to ion channel opening.

Topics: Acrosome; Animals; Arachidonic Acid; Arachidonic Acids; Dose-Response Relationship, Drug; Dronabinol; Endocannabinoids; Fertilization; Ionomycin; Male; Nigericin; Ovum; Polyunsaturated Alkamides; Receptors, Cannabinoid; Receptors, Drug; Sea Urchins; Spermatozoa