Abstract

Recently, laser light has been employed as the illumination of the transcatheter intravascular endoscope, and as energy for ablation in angioplasty. Although the phenomena on blood vessels by light irradiation are extremely interesting, it has not been studied in detail. We previously reported that vascular rings of the rat thoracic aorta reproducibly showed either contraction or relaxation during low-power laser irradiation. Laser-induced vasocontraction and relaxation were investigated to determine whether these tension changes were due to the thermal effect or not. Vascular rings were suspended isometrically under resting tension of 1.0 g, and precontracted with norepinephrine (10^-6 M). Various laser lights were delivered via an optical fiber (ϕ = 300 μm) to a small spot on the adventitial surface. The isometric tension of the rat aortic rings was measured with the same deposited energy in the ring at each wavelength (λ = 351 nm, 458 nm, 514.5 nm; Argon ion laser. λ = 800 nm; Ti:Sapphire laser.)

© 1995 IEEE