An analysis of neuronal responses in nucleus centrum medianum to electrical stimulation of the superficial peroneal nerve.
Excitatory and inhibitory responses recorded extracellularly in neurons at various levels of the central nervous system induced by electrical noxious stimulation of peripheral nerves were frequently reported in studies on the mechanisms of acupuncture analgesia. However, the correlation between the responses and excitation of distinct afferent fibers was rarely investigated. The question whether the responses mentioned above are truly nociceptive in property is of significance to answer, and this is what we want to clarify in the present study. Sixty five neurons responding to electrical stimulation of the left superficial peroneal nerve were extracellularly recorded in the nucleus centrum medianum (CM) contralateral to the stimulation in 34 cats paralyzed with gallamine triethiodide and ventilated artificially under anaesthetics. Peristimulus histograms of the responses of CM neurons were plotted correspondingly, to the excitation of A delta and C-fibers, which was monitored by means of compound action potentials. To identify the nociceptive property of the responses ketamine or morphine was intravenously administered in some cases, capsaicin was topically applied at the superficial peroneal nerve proximal to the stimulated location in a few cases. Besides, the effect of electroacupuncture (EA) at Zusanli (St36) and Huantiao (GB30) points on the responses was observed. A total of 65 CM neurons recorded included 55 excited and 10 inhibited neurons.(ABSTRACT TRUNCATED AT 250 WORDS)
Chen
Z
Z
Institute of Acupuncture, China Academy of Traditional Chinese Medicine, Beijing.
Yan
Y
Y
Wang
K
K
Xu
W
W
Shi
T
T
D000200:Action Potentials; D000818:Animals; D002415:Cats; D004558:Electric Stimulation; D015671:Electroacupuncture; D007649:Ketamine / Q000494:pharmacology; D009020:Morphine / Q000494:pharmacology; D009412:Nerve Fibers / Q000502:physiology; D009474:Neurons / Q000502:physiology; D009619:Nociceptors / Q000502:physiology*; D010146:Pain / Q000503:physiopathology; D010543:Peroneal Nerve / Q000502:physiology; D013787:Thalamic Nuclei / Q000502:physiology*
D007649:Ketamine; D009020:Morphine