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Possible Mechanisms of Vascular Relaxation Induced by Pulsed‐UV Laser
Author(s) -
Morimoto Yuji,
Arai Tsunenori,
Matsuo Hirotaka,
Kikuchi Makoto
Publication year - 1998
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1998.tb09697.x
Subject(s) - irradiation , fluence , ablation , laser , chemistry , excimer laser , methylene blue , materials science , biophysics , optics , medicine , biochemistry , physics , nuclear physics , biology , catalysis , photocatalysis
This study was designed to examine the mechanism of vasorelaxation induced by pulsed‐UV laser. Luminal diameters of rat femoral arteries were measured prior to and following krypton‐fluoride excimer laser irradiation of 248 nm in wavelength. The diameter was enlarged to 1.3 times the preirradiated size at 1 or 10 Hz irradiation when the fluence was over 2.0 mj/pulse/mm 2 , while the diameter reached 1.8 times at 100 Hz with a fluence of 0.8 mj/pulse/mm 2 . Vasorelaxation by the 100 Hz irradiation was inhibited when the artery was pretreated with methylene blue but was enhanced with superoxide dis‐mutase. Pathological analysis revealed an ablation crater and vacuole formation in the vessel at 1 or 10 Hz irradiation, but these changes were not remarkable in the 100 Hz‐exposed sample. These findings suggest that vasorelaxation induced by the pulsed UV irradiation at 1 or 10 Hz results from structural alteration of vascular smooth muscle by the ablation crater or vacuolization. On the other hand, a possible mechanism of vasorelaxation at the 100 Hz irradiation is partially related to nitric oxide.