按祖国医学理论

针刺作用为外因通过体内各调节系统产生效应

针刺镇痛则可能是通过体内抗痛调节系统而实现。国内外通过吗啡镇痛的研究提出体内存有一内在的抗痛系统。富有阿片受体的脑室—导水管周围灰质(pAG)是吗啡镇痛的高效区

电刺激该区也能获得强的镇痛效应

毁损该区则可减弱镇痛效应

Our previous experiments revealed that both the endogeneous opiate systemand the descending serotonergic inhibitory system take part in acupunctureanti-visceralgia.In the present study the correlation between the actions ofthese two systems was further investigated.Experiments were carried out on male

awake and restrained rats.When aconstant current of 100 μA was used to stimulate the through implanted concen-tric electrode laid beforehand in NRM

an anti-visceralgia effect(expressed bysupression of splanchnic nociceptive defensive reflex)could be seen.However

this inhibitory effect was markedly blocked(n=11

p<0.01)by 20 minutespretreatment of naloxone(1mg/kg i.p.).At 60-150 minutes after adminis-tration

NRM stimulation produced analgesia was gradually intensified butnot completely recovered.According to these findings

it is speculated that 5-HT released fromserotonergic terminals in spinal cord exerts inhibitory control on nociceptiveinformation

at least in part

by activating the enkephalinergic nurones torelease enkephalin which may be involved in primary afferent depolarization.However

the mode of action in detail remains to be investigated.