Arachidonoylserotonin and other novel inhibitors of fatty acid amide hydrolase

Biochem Biophys Res Commun. 1998 Jul 30;248(3):515-22. doi: 10.1006/bbrc.1998.8874.


Fatty acid amide hydrolase (FAAH) catalyzes the hydrolysis of bioactive fatty acid amides and esters such as the endogenous cannabinoid receptor ligands, anandamide (N-arachidonoyl-ethanolamine) and 2-arachidonoylglycerol, and the putative sleep inducing factor cis-9-octadecenoamide (oleamide). Most FAAH blockers developed to date also inhibit cytosolic phospholipase A2 (cPLA2) and/or bind to the CB1 cannabinoid receptor subtype. Here we report the finding of four novel FAAH inhibitors, two of which, malhamensilipin A and grenadadiene, were screened out of a series of thirty-two different algal natural products, and two others, arachidonoylethylene glycol (AEG) and arachidonoyl-serotonin (AA-5-HT) were selected out of five artificially functionalized polyunsaturated fatty acids. When using FAAH preparations from mouse neuroblastoma N18TG2 cells and [14C]anandamide as a substrate, the IC50s for these compounds ranged from 12.0 to 26 microM, the most active compound being AA-5-HT. This substance was also active on FAAH from rat basophilic leukaemia (RBL-2H3) cells (IC50 = 5.6 microM), and inhibited [14C]anandamide hydrolysis by both N18TG2 and RBL-2H3 intact cells without affecting [14C]anandamide uptake. While AEG behaved as a competitive inhibitor and was hydrolyzed to arachidonic acid (AA) by FAAH preparations, AA-5-HT was resistant to FAAH-catalyzed hydrolysis and behaved as a tight-binding, albeit non-covalent, mixed inhibitor. AA-5-HT did not interfere with cPLA2-mediated, ionomycin or antigen-induced release of [3H]AA from RBL-2H3 cells, nor with cPLA2 activity in cell-free experiments. Finally, AA-5-HT did not activate CB1 cannabinoid receptors since it acted as a very weak ligand in in vitro binding assays, and, at 10-15 mg/kg body weight, it was not active in the 'open field', 'hot plate' and rectal hypothermia tests carried out in mice. Conversely AEG behaved as a cannabimimetic substance in these tests as well as in the 'ring' immobility test where AA-5-HT was also active. AA-5-HT is the first FAAH inhibitor reported to date which is inactive both against cPLA2 and at CB1 receptors, whereas AEG represents a new type of cannabinoid receptor agonist.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amidohydrolases / antagonists & inhibitors*
  • Animals
  • Arachidonic Acids / chemistry
  • Arachidonic Acids / metabolism
  • Arachidonic Acids / pharmacology*
  • Cyclopropanes / chemistry
  • Cyclopropanes / pharmacology
  • Endocannabinoids
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / pharmacology*
  • Esters / chemistry
  • Esters / pharmacology
  • Ethylene Glycols / chemistry
  • Ethylene Glycols / pharmacology
  • Kinetics
  • Leukemia, Basophilic, Acute
  • Lipids / chemistry
  • Lipids / pharmacology
  • Mice
  • Neuroblastoma
  • Polyunsaturated Alkamides
  • Rats
  • Serotonin / analogs & derivatives*
  • Serotonin / chemistry
  • Serotonin / pharmacology
  • Structure-Activity Relationship
  • Substrate Specificity
  • Tumor Cells, Cultured


  • Arachidonic Acids
  • Cyclopropanes
  • Endocannabinoids
  • Enzyme Inhibitors
  • Esters
  • Ethylene Glycols
  • Lipids
  • Polyunsaturated Alkamides
  • arachidonoylethylene glycol
  • arachidonoylserotonin
  • grenadadiene
  • malhamensilipin A
  • Serotonin
  • Amidohydrolases
  • fatty-acid amide hydrolase
  • anandamide