Abstract
Purpose :
Transient receptor potential vanilloid subtype (TRPV) channels are non-selective cation channels expressed in both endothelium and vascular smooth muscle cells in various vascular beds. These channels can be activated by endogenous ligands, heat, shear stress, and cell swelling, and regulate the vascular tone. However, it remains unclear whether TRPV channels influence the retinal microcirculation. Herein, we examined the effects of TRPV1 and TRPV4 agonists on the retinal arterioles.
Methods :
Porcine retinal arterioles were isolated, cannulated, and pressurized without flow in vitro. Diameter changes were recorded using microscopic video techniques.
Results :
TRPV1 agonist capsaicin did not alter the vessel diameter (P > 0.05). In contrast, TRPV4 agonist GSK1016790A significantly induced dose-dependent vasodilation of the retinal arterioles (P < 0.0001). The highest concentration (1 µM) elicited approximately 20% of the maximal dilation. This vasodilatory response to GSK1016790A was reduced by incubation with TRPV4 antagonist HC-067074 (1 µM, P < 0.005).
Conclusions :
TRPV4 agonist GSK1016790A induces vasodilation of the retinal arterioles in a dose-dependent manner. The current findings suggest that TRPV4 may be involved with the regulation of retinal blood flow.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.