Responses of Primary Afferent Fibers to Acupuncture-Like Peripheral Stimulation at Different Frequencies:Characterization by Single-Unit Recording in Rats

The pain-relieving effect of acupuncture is known to involve primary afferent nerves(PANs) via their roles in signal transmission to the CNS.Using single-unit recording in rats,we characterized the generation and transmission of electrical signals in Aβ and Aδ fibers induced by acupuncture-like stimuli.Acupuncture-like signals were elicited in PANs using three techniques:manual acupuncture(MAc),emulated acupuncture(EAc),and electro-acupuncture(EA)-like peripheral electrical stimulation(PES).The discharges evoked by MAc and EAc were mostly in a burst pattern with average intra-burst and inter-burst firing rates of 90 Hz and 2 Hz,respectively.The frequency of discharges in PANs was correlated with the frequency of PES.The highest discharge frequency was 246 Hz in Aβ fibers and 180 Hz in Aδ fibers.Therefore,EA in a dense-disperse mode(at alternating frequency between 2 Hz and 15 Hz or between 2 Hz and 100 Hz) best mimics MAc.Frequencies of EA output>250 Hz appear to be obsolete for pain relief.

Neuromechanism of acupuncture regulating gastrointestinal motility

Acupuncture has been used in China for thousands of years and has become more widely accepted by doctors and patients around the world. A large number of clinical studies and animal experiments have confirmed that acupuncture has a benign adjustment effect on gastrointestinal(GI) movement;however, the mechanism of this effect is unclear, especially in terms of neural mechanisms, and there are still many areas that require further exploration. This article reviews the recent data on the neural mechanism of acupuncture on GI movements. We summarize the neural mechanism of acupuncture on GI movement from four aspects: acupuncture signal transmission, the sympathetic and parasympathetic nervous system, the enteric nervous system, and the central nervous system.

PLASMA EXTRAVASATION IN THE VISCERAL ORGANS CAUSED BY ELECTRICAL STIMULATION OF ACUPOINT "ZUSANLI" IN RATS

Objective To investigate the plasma extravasation of visceral organs caused by electrical stimulation of acupoint under the dorsal root reflex and axon reflex conditions. Methods By the means of measuring the content of Evans blue, this study investigated the plasma extravasation of visceral organs induced by electrical stimulation of acupoint 'Zusanli'(ST 36).Results The Evans blue content in the visceral organs such as liver, spleen, pancreas and the whole gastrointestinal tract in rats increased significantly after electrical stimulation of acupoint 'Zusanli' compared with that of the control group (P<0.01). The Evans blue extravasation in the above visceral organs was blocked by pre-treatment of capsaicin (66 mmol·L -1, 50 μL) into the acupoint. Conclusion The neurogenic inflammation of the visceral organs evoked by electrical stimulation of acupoint was mediated by the capsaicin-sensitive afferent fibers through the dorsal root reflex and axon reflex. It is a new method to study the correlation of meridian-viscera.