Affinin, isolated from Heliopsis longipes, induces an antihypertensive effect that involves CB1 cannabinoid receptors and TRPA1 and TRPV1 channels activation.

In previous studies we demonstrated that the ethanolic extract of Heliopsis longipes roots (EEH) and its main alkamide, affinin, elicit a vasorelaxant effect through a mechanism involving activation of the gasotransmitters pathways and stimulation of CB1 receptors and TRPA1 and TRPV1 channels. However, it has not yet been demonstrated whether EEH and affinin are capable of lowering high blood pressure. Therefore, the aim of the present study was to determine the effect of oral administration of EEH and affinin on the systolic blood pressure of L-NAME-induced hypertensive rats and to explore the participation of cannabinoid receptors and TRP channels in the mechanism of action of this alkamide. Our results showed that EEH and affinin significantly lowered systolic blood pressure and induce an improvement in endothelial function, which is associated with increased serum NO levels. Inhibition of CB1 receptors by rimonabant (3 mg/kg), TRPA1 channels by HC-030031 (8 mg/kg), and TRPV1 channels by capsazepine (5 mg/kg) significantly decreased the antihypertensive effect induced by affinin, suggesting that the blood pressure lowering effect of this alkamide involves activation of CB1 receptors and TRPA1 and TRPV1 channels.