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International Journal of Photoenergy
Volume 2014, Article ID 275765, 8 pages
Research Article

Inhibitory Effects of 658 nm Laser Irradiation on Skin Temperature in Anesthetized Rats: Preliminary Results from a Controlled Study

1Research Unit for Complementary and Integrative Laser Medicine, Research Unit of Biomedical Engineering in Anesthesia and Intensive Care Medicine and TCM Research Center Graz, Medical University of Graz, Auenbruggerplatz 29, 8036 Graz, Austria
2Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China
3Research Group Developmental Psychopharmacology, Institute of Psychopharmacology, Central Institute of Mental Health, University of Heidelberg, 68159 Mannheim, Germany

Received 4 February 2014; Accepted 18 February 2014; Published 7 April 2014

Academic Editor: Lu Wang

Copyright © 2014 Daniela Litscher et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Red laser light stimulation can have many physiological effects. The goal of this animal experimental study was to investigate how red laser stimulation influences the temperature of anesthetized rats at different acupuncture points and nonacupoints. For that reason 12 adult male Wistar Han rats (300–380 g) were investigated. Six anesthetized rats underwent red laser stimulation (wavelength 658 nm, output power 40 mW, diameter 500 µm, and duration 10 min) at the Baihui (GV20) acupoint, the Zusanli acupoint (ST36, bilateral), and a control point on the forelimb. The other six rats underwent the same procedure; however, the laser remained switched off. Significant decreases in temperature were found at the acupoints Baihui, Zusanli left, and Zusanli right. In addition there was no significant temperature effect at a control point. During placebo laser irradiation (deactivated laser) there were also significant temperature changes. The mechanism underlying the results is currently unknown, but brain stimulation (via laser or mechanical pressure) and mainly direct central mechanisms may be responsible for the local and peripheral temperature decrease.