P8.02: Characterization of the Vasorelaxant Mechanisms of Endocannabinoid Oleoylethanolamide in the Bovine Ophthalmic Artery

Background Numerous studies show the potential therapeutic effect of different endocannabinoids and in particular the vasorelaxant effects in several vascular beds Aim To evaluate the vasorelaxant effect of oleoylethanolamide on isolated bovine ophthalmic arteries and to evaluate the possible mechanisms involved in relaxant responses. Methods Ophthalmic arteries were isolated from bovine eyes and mounted in a wire miograph for isometric tension recording. The effects time- and concentration-dependent were assayed by addition of the oleoylethanolamide to the organ bath. Results Oleoylethanolamide (0.1 – 10 µM) produced a significant concentration- and time-dependent vasorelaxation in the bovine ophthalmic artery pre-contracted with 5-HT (1 µM). The removal of endothelium provoked a slight reduction of the relaxant effects. Interestingly, a pre-treatment with antagonist PPARα GW6471 (1 µM) inhibited the concentration- and time-dependent oleoylethanolamide-induced vasorelaxation. Conclusion The present study shows that oleoylethanolamide relaxed the isolated bovine ophthalmic artery in the concentration- and time-dependent manner. The candidate responsible of the vasorelaxant response to oleoylethanolamide appear to be the PPARα. This relaxant effect is an exciting tool to prevent ischemic injury because it improves the blood supply to the retina.