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 amidohydrolase activity present in rat brain and liver, We report that the bromoenol lactone, (E)-6-(bromomethylene) tetrahydro-3-(1-naphthalenyl)-2H-pyran-2-one (BTNP), is a potent inhibitor of this enzyme activity, BTNP prevented anandamide hydrolysis in rat brain microsomes with an IC50 of 0.8+/-0.3 mu M. Kinetic and dialysis experiments indicated that this effect was non-competitive and irreversible, After chromatographic fractionation of the enzyme activity, BTNP was still effective, suggesting that it interacts directly with the enzyme, Anandamide hydrolysis 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.