针刺可以抑制痛觉的皮层下各中枢神经元的活动

已有大量的实验证明

而大脑皮层在痛觉的产生以及在针刺镇痛中的作用已有报道

但目前尚无一致的意见。本室过去的工作已证实

中脑网状结构(Mesencephalic Reticular Formation

MRF)对痛觉不仅起着传导通路的作用

而in order to investigate the effect of stimulation of the cortical somatic sensory area(SII)on the nociceptive discharges in the mesencephalon reticular formation

and its role in acupuncture analgesia

experiments were performed on 55 rabbits

anesthetized with chloralose and urethane. As soon as the animal recovered its conciousness it was immobilized with flaxedil and artificial respiration given.The electrical activities of the nocicep(ive neurons were recorded by glass microelectrodes(tip 1～3μ)in the ranges P_(7～11)

R_(2～3)

_(0～6)

with the aid of a stercotaxic apparatus. 81 of the nociceptive units recorded responded to noxious stimuli which werc applied to the peronal nerve with a short train of pulses.Among them

65 units

that is 80%

responded by an increase in frequency of the discharge to nonious stimuli(pain-excition neuron

PEN).In contrast

there were 16 units

that is 20%

which responded to noxious stimuli quite differently

by having a decrease in the frequency of the discharge(pain-inhibition neuron

PIN).Similar results were obtained by stimulation of area SII of the cortex with the same train of pulses:an excitatory effect was observed in PEN

and an inhibitory effect in PIN.However

after electroacupucture by penetrating“Neiguan”point towards“Waiguan”point

or dolantin was given intravenously

under the same conditions used above

we stimulated both the peroneal nerve and area SII

elicited an inhibitory effect on PEN

and a reduction of inhibition or release from it on PIN. From the results presented

it is indicated that area SII of the cortex is connected with the modulation of the nociceptive neuronal activity in mesencephalon reticular formation and is related to the effect of acupuncture.