Acupuncture stimulation inhibits somato-renal sympathetic A- and C-reflexes in anesthetized rats

Stimulation of peripheral nerve afferent for example tibial nerve by a strong electrical stimulation (rectanfular wave with 20V amplitude; pulse duration of 0.5 ms, 0.3 pulses/sec) can evoke a discharge of the somato-sympathetic reflex which is recorded on the efferent of renal sympathetic nerve. The component of the somato-sympathetic reflex can be divided into two parts: one is related to the transmission of the myelinated afferent fibers with a short lantency (41+/-2 ms) and is defined A-reflex, the other is related to the transmission of the unmyelinated afferent fibers with a long latency (210+/-13 ms) and is defined C-reflex. In the present study, an acupuncture needle (diameter 0.34 mm) was inserted into the hind limbs of the rat, dorsolaterally at the area of acupoint: huantiao (GB30), at a depth of 4-5 mm and was twisted right and left twice every second during recording the somato-renal sympathetic reflex. It was found that acupuncture on the huantiao acupoint significantly inhibited both A- and C-reflexes. There was no different inhibition of the A- and C-reflexes by acupuncture on the right or left side. However acupuncture on the fore limbs of the rat dorsolaterally at the area of acupoint: quchi (LI11) showed no effect on neither A- nor C-reflexes. These results suggest that acupuncture at the same spinal segment of the acupoint inhibits the somatorenal sympathetic reflex.