INHIBITION OF ANANDAMIDE HYDROLYSIS IN RAT-BRAIN TISSUE BY (E)-6-(BROMOMETHYLENE) TETRAHYDRO-3-(1-NAPHTHALENYL)-2H-PYRAN-2-ONE

Anandamide, an endogenous cannabinoid substance, is hydrolyzed by an a midohydrolase activity present in rat brain and liver, We report that the bromoenol lactone, (E)-6-(bromomethylene) tetrahydro-3-(1-naphthal enyl)-2H-pyran-2-one (BTNP), is a potent inhibitor of this enzyme acti vity, BTNP prevented anandamide hydrolysis in rat brain microsomes wit h an IC50 of 0.8+/-0.3 mu M. Kinetic and dialysis experiments indicate d that this effect was non-competitive and irreversible, After chromat ographic fractionation of the enzyme activity, BTNP was still effectiv e, suggesting that it interacts directly with the enzyme, Anandamide h ydrolysis was 12-fold greater in rat cortical neurons (1.94+/-0.1 pmol /min/mg protein) than in cortical astrocytes (0.16+/-0.01 pmol/min/mg protein) and, in either cell type, it,vas inhibited by BTNP (IC50=0.1 mu M in neurons), These results suggest that BTNP may provide a useful lead for the development of novel inhibitors of anandamide hydrolysis . (C) Federation of European Biochemical Societies.