title: Inhibition of fatty acid amidohydrolase, the enzyme responsible for the metabolism of the endocannabinoid anandamide, by analogues of arachidonoyl-serotonin.
abstract: Arachidonoyl-serotonin inhibits in a mixed-type manner the metabolism of the endocannabinoid anandamide by the enzyme fatty acid amidohydrolase. In the present study, compounds related to arachidonoyl-serotonin have been synthesised and investigated for their ability to inhibit anandamide hydrolysis by this enzyme in rat brain homogenates. Removal of the 5-hydroxy from the serotonin head group of arachidonoyl-serotonin produced a compound (N-arachidonoyltryptamine) that was a 2.3-fold weaker inhibitor of anandamide hydrolysis, but which also produced its inhibition by a mixed-type manner (Ki(slope) 1.3 microM; Ki(intercept) 44 microM). Replacement of the amide linkage in this compound by an ester group further reduced the potency. In contrast, replacement of the arachidonoyl side chain by a linolenoyl side chain did not affect the observed potency. N-(Fur-3-ylmethyl) arachidonamide (UCM707), N-(fur-3-ylmethyl)linolenamide and N-(fur-3-ylmethyl)oleamide inhibited anandamide hydrolysis with pI50 values of 4.53, 5.36 and 5.25, respectively. The linolenamide derivative was also found to be a mixed-type inhibitor. It is concluded that the 5-hydroxy group of arachidonoyl-serotonin contributes to, but is not essential for, inhibitory potency at fatty acid amidohydrolase.
mesh_terms: D000581:Amidohydrolases / Q000037:antagonists & inhibitors*; D000818:Animals; D001095:Arachidonic Acids / Q000378:metabolism* / Q000494:pharmacology*; D001665:Binding Sites; D001921:Brain / Q000378:metabolism; D063385:Cannabinoid Receptor Modulators; D004305:Dose-Response Relationship, Drug; D063388:Endocannabinoids; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006868:Hydrolysis; D020128:Inhibitory Concentration 50; D007700:Kinetics; D008956:Models, Chemical; D053284:Polyunsaturated Alkamides; D051381:Rats; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug / Q000378:metabolism; D012701:Serotonin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D000099252:Fatty Acid Amide Hydrolases
chemical_list: D000581:Amidohydrolases; D001095:Arachidonic Acids; D063385:Cannabinoid Receptor Modulators; D063388:Endocannabinoids; D004791:Enzyme Inhibitors; D053284:Polyunsaturated Alkamides; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug; D012701:Serotonin; D000099252:Fatty Acid Amide Hydrolases; C114007:arachidonoylserotonin; C078814:anandamide