Contribution of adenosine to the increase in skeletal muscle blood flow caused by manual acupuncture in rats.
OBJECTIVE
Adenosine is believed to play an important role in local acupuncture analgesia. The aim of this study was to investigate the contribution of adenosine to the increase in skeletal muscle blood flow (MBF) caused by manual acupuncture (MA).


METHODS
Thirty-two male Sprague-Dawley rats (310-360 g) were anaesthetised and divided into four equal groups (n=8 each): Saline, Saline+MA, Theophylline, and Theophylline+MA. In the two MA groups, the sparrow-pecking MA technique was applied at 30 repetitions per min for 1 min to a depth of 15-18 mm using a stainless steel acupuncture needle (0.20×40 mm). The stimulus point was located on the right tibialis anterior (TA) muscle 7-8 mm below the knee. Animals in the two theophylline groups were intra-arterially injected with 8-(p-sulphophenyl) theophylline, a non-selective adenosine receptor antagonist, at a dose of 30 mg/kg before MA. Animals in the two saline groups received control saline. Fluorescent microspheres (15 µm in diameter, yellow-green fluorescent) were used for MBF measurement in all four groups.


RESULTS
MA of the TA muscle significantly increased MBF (Saline+MA vs Saline: p=0.001; Saline+MA vs Theophylline: p=0.008). Pre-treatment with theophylline appeared to inhibit this increase (Theophylline vs Theophylline+MA; p=1.000). MBF in the Theophylline+MA group was 43% lower than in the Saline+MA group, although this was not significantly different (p=0.104).


CONCLUSIONS
The results suggest that adenosine leads to an increase in MBF caused by MA. Adenosine may play a role in acupuncture analgesia by washing out algesic substances. Further studies are needed in order to elucidate the precise mechanism.
Department of Basic Acupuncture and Moxibustion, Meiji University of Integrative Medicine, Nantan-shi, Kyoto, Japan.
Hisashi
H
Shinbara
Department of Basic Acupuncture and Moxibustion, Meiji University of Integrative Medicine, Nantan-shi, Kyoto, Japan.
Satomi
S
Nagaoka
Department of Basic Acupuncture and Moxibustion, Meiji University of Integrative Medicine, Nantan-shi, Kyoto, Japan.
Yasuyuki
Y
Izutani
Department of Anatomy and Neuroscience, Hyogo College of Medicine, Nishinomiya-shi, Hyogo, Japan.
Masamichi
M
Okubo
Department of Health Promoting and Geriatric Acupuncture and Moxibustion, Meiji University of Integrative Medicine, Nantan-shi, Kyoto, Japan.
Keisaku
K
Kimura
Department of Health Promoting and Geriatric Acupuncture and Moxibustion, Meiji University of Integrative Medicine, Nantan-shi, Kyoto, Japan.
Kunio
K
Mizunuma
Department of Basic Acupuncture and Moxibustion, Meiji University of Integrative Medicine, Nantan-shi, Kyoto, Japan.
Eiji
E
Sumiya
D015667:Acupuncture Analgesia; D015669:Acupuncture Points; D015670:Acupuncture Therapy; D000241:Adenosine / Q000378:metabolism*; D000818:Animals; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow
D000241:Adenosine
ACUPUNCTURE