Hydrolysis of anandamide and eicosapentaenoic acid ethanolamide in mouse splenocytes

The hydrolysis of anandamide has been studied in mouse splenocytes using tr itiated anandamide analogs labeled in the acyl- or ethanolamide parts of th e molecule. [H-3]Anandamide undergoes rapid (t(1/2) = 2.5 min) uptake and h ydrolysis, yielding ethanolamine and arachidonic acid. The anandamide hydro lysis in splenocytes is sensitive to inhibition by phenylmethylsulfonyl flu oride, and it is assumed that the observed activity is due to fatty acid am ide hydrolase, which inactivates anandamide in central and peripheral tissu es. Eicosapentaenoic acid ethanolamide and the 15-hydroxy-derivative of ana ndamide are shown to be amidohydrolase substrates as well. The fatty acids derived from hydrolytic cleavage of acylethanolamines undergo rapid oxidati on by splenocyte lipoxygenase, yielding the corresponding 12-hydroxy-deriva tives. Oxygenated ethanolamide derivatives were not found. The data suggest that polyenoic fatty acid ethanolamides are metabolic precursors of eicosa noids in splenocytes and that amide bond hydrolysis is the key point in swi tching of biological activity spectra between endocannabinoids and oxylipin s.