TRPV4 Agonists Dilate Retinal Arterioles in Rats

The impaired retinal circulation contributes to the onset and progression of glaucoma and diabetic retinopathy, leading to vision loss or blindness. In this study, we examined whether GSK1016790A, an activator of TRPV4, improves retinal circulation in rats. Ocular fundus images were captured and diameters of retinal blood vessels contained in the images were measured. Both systemic blood pressure and heart rate were continuously recorded. Intravenous infusion of GSK1016790A (0.2-2 μg/kg/min) increased retinal arteriolar diameter in a dose-dependent manner. The higher dose of GSK1016790A (2 μg/kg/min) slightly decreased blood pressure without changing heart rate. These responses to GSK1016790A were significantly attenuated by intravenous injection of GSK2193874 (0.3 mg/kg), an antagonist of TRPV4. These results suggest that agonists of TRPV4 dilate retinal arterioles more strongly than peripheral arteries. Thus, TRPV4 agonists may improve retinal circulation and become one candidate of therapeutics for preventing the development of ocular diseases, which are associated with impaired retinal circulation. Poster Sessions