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PURPOSE We investigated the vasodilatory action of FK 409 on bovine retinal arteries using a microvessel perfusion system in vitro. MATERIALS AND METHODS Bovine retinal arteries were obtained from bovine eyes. The arteries, 3 mm long and 110 microns in diameter, were attached to the microvessel perfusion system. The arteries were perfused with Tyrode solution containing 10(-6) M U46619, followed by 10(-6) M U46619 and FK 409 (10(-3) M or 10(-4) M). We also perfused the arteries with carboxy-2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide. The inner diameter of the arteries was measured under a microscope and analyzed by computer. RESULTS FK 409 prevented contraction of bovine retinal arteries induced by perfusion of 10(-6) M U46619 when the arteries were perfused with 10(-3) to 10(-4) M FK 409. Addition of 100 microM PTIO, an nitric oxide (NO)-specific extinction agent, into the mixture of U46619 and FK 409 hadan antagonistic effect on the contractive action of FK 409. CONCLUSION These results suggest that FK 409 has a dilatational effect on bovine retinal arteries and that the dilatational action of FK 409 is possibly produced by NO. |
