Endothelial TRP channels and cannabinoid receptors are involved in affinin-induced vasodilation

Abstract

Affinin is mainly recognized by its antinociceptive effect. Recently, our research group demonstrated that this compound produces vasodilation via activation of the gasotransmitters signaling pathways. However, the molecular targets of affinin were not identified. Considering the structural similarity of this alkamide with anandamide, we hypothesized that affinin-induced vasodilation could involve participation of TRP channels and cannabinoid receptors. In this work, by using the isolated rat aorta assay, we assessed involvement of TRP channels, the cannabinoid system, and the HNO-CGRP-TRPA₁ pathway on the mechanism of action of affinin. Additionally, we measured NO and H₂S levels elicited by affinin on rat aorta homogenates and carried out computer simulations of molecular interactions between affinin and the TRPA₁ and TRPV₁ channels and the CB₁ receptor. Our results indicated that affinin induces an increase in aortic NO and H₂S levels. We found evidence that the vasodilator effect induced by affinin involves activation of TRPA₁ and TRPV₁ channels and the CB₁ and eCB receptors. In silico analyses showed that affinin is able to bind with high affinity to these molecular targets. Moreover, we also proved that affinin-induced vasodilation is partly mediated via activation of the HNO-TRPA₁-CGRP pathway. Based on these results we propose a novel mechanism of action to explain the vasodilatory effect of affinin, which could be developed as an alternative drug to treat cardiovascular diseases.

Keywords: Affinin; Cannabinoid receptors; HNO-TRPA(1)-CGRP pathway; Spilanthol; TRP channels; Vasodilation.