Zhen Ci Yan Jiu. 1991 ; 16(2): 79-86.

[Response properties of SI cortical neurons to electro-acupuncture and manual acupuncture in the rat]

Yuan B, Pang T, Liu X.

Research Laboratory of Neurophysiology, Xi'an Medical University.

Single SI cortical neurons were recorded extracellularly with glass micropipettes, and their response properties to electro-acupuncture (EA) of contralateral Tsusanli (St. 36) and Fenglung (St. 40), or to manual acupuncture (MA) of Tsusanli were observed in unanesthetized and paralyzed rats. In 46 rats, a total of 474 neurons were isolated in the hindlimb representation area of SI cortex. Among these neurons, 228 responded to peripheral mechanical stimulation, and could be classified as cutaneous neurons, deep neurons and cutaneous-deep convergent neurons. Thirty five of them were identified as nociceptive neurons. Neurons of various sensory neurons and with receptive fields (RFs) located in the contralateral hindlimb responded to EA. Significant difference (P less than 0.01) existed between the stimulation thresholds of cutaneous neurons (2.39 +/- 0.27V) and those of deep neurons (4.12 +/- 0.48V). There was no significant difference between the thresholds of nociceptive and non-nociceptive neurons. The typical response of SI neurons to single EA stimulation consisted of early discharges with a latency of 11.57 +/- 0.39 msec and late train discharges with a latency of 54.79 +/- 4.07 msec. A period of inhibition frequently intervened between the two groups of discharges. In a small portion of neurons, only a period of inhibition was produced. The responsiveness of neurons decreased markedly when the frequency of repeated EA stimulation was increased from 1 Hz to 50 Hz. Neurons of various sensory modalities responded to MA as well. Judging by RF distribution of the responsive neurons, however, the extent of action of MA was smaller than that of EA.(ABSTRACT TRUNCATED AT 250 WORDS)