CONICET | Buscador de Institutos y Recursos Humanos

Anandamide binds to cannabinoid receptors and plays several central and peripheral functions. The aim of this work was to study the possible role for this endocannabinoid in controlling sperm-oviduct interaction in mammals. We observed that bull sperm and bovine oviductal epithelial cells express cannabinoid receptors, CB1 and CB2 and fatty acid amide hydrolase, the enzyme that controls intracellular anandamide levels. A quantitative assay to determine if anandamide was involved in bovine sperm-oviduct interaction was developed. R(+)-Methanandamide, a non-hydrolysable anandamide analogue, inhibited sperm binding to and induced sperm releasing from oviductal epithelia. Selective CB1 antagonists (SR141716A or AM251) completely blocked R(+)-Methanandamide effect. However, SR144528, a selective CB2 antagonist, did not exert any effect, indicating that only CB1 was involved in R(+)-Methanandamide effect. This effect was not caused by inhibition of the sperm progressive motility or by induction of the acrosome reaction. Overall, our findings indicate for the first time that the endocannabinoid system is present in bovine sperm and oviductal epithelium and that anandamide modulates the sperm-oviduct interaction, by inhibition of sperm binding and induction of sperm release from oviductal epithelial cells, probably by activating CB1 receptors.