Effects of near-infrared low-level laser irradiation on microcirculation.
OBJECTIVE
Recently, there has been an increase in the clinical application of low-level laser irradiation (LLLI) in various fields. The present study was conducted to explore the effects of LLLI on microcirculation.


METHODS
We investigated the effects of LLLI on rat mesenteric microcirculation in vivo, and on cytosolic calcium concentration ([Ca2+]i) in rat vascular smooth muscle cells (VSMCs) in vitro.


RESULTS
LLLI caused potent dilation in the laser-irradiated arteriole, which led to marked increases in the arteriolar blood flow. The changes were partly attenuated in the initial phase by the superfusion of 15 microM L-NAME, but they were not affected by local denervation. Furthermore, LLLI caused a power-dependent decrease in [Ca2+]i in VSMCs.


CONCLUSIONS
The circulatory changes observed seemed to be mediated largely by LLLI-induced reduction of [Ca2+]i in VSMCs, in addition to the involvement of NO in the initial phase.
Maegawa
Y
Y
Department of Anesthesiology, Kyoto Prefectural University of Medicine, Japan.
Itoh
T
T
Hosokawa
T
T
Yaegashi
K
K
Nishi
M
M
D000818:Animals; D001160:Arterioles / Q000294:innervation / Q000502:physiology / Q000528:radiation effects; D001783:Blood Flow Velocity / Q000528:radiation effects; D002118:Calcium / Q000378:metabolism; D003714:Denervation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066298:In Vitro Techniques; D007834:Lasers; D008297:Male; D008643:Mesentery / Q000098:blood supply*; D008833:Microcirculation / Q000528:radiation effects; D009131:Muscle, Smooth, Vascular / Q000378:metabolism / Q000528:radiation effects; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D011829:Radiation Dosage; D051381:Rats; D017208:Rats, Wistar; D014664:Vasodilation / Q000528:radiation effects
D004791:Enzyme Inhibitors; D019001:Nitric Oxide Synthase; D002118:Calcium; D019331:NG-Nitroarginine Methyl Ester