中缝背核和蓝斑在唇针镇痛中的作用

<正> 我们以往的实验表明,脑内5-羟色胺能神经原系统是实现唇针镇痛的必要条件。破坏或减弱这个系统的神经传递,唇针的镇痛效应降低;相反,激活或加强这个系统的神经传递,则唇针的镇痛效应升高.同时也有资料提示,脑内去甲肾上腺素能神经原系统对针刺镇痛可能起着某种拮抗作用.此外,近年来的形态研究资料表明,在5-羟色胺能神经原胞体主要集中的中缝背核和去甲肾上腺素能神经原胞体主要集中的蓝斑之间有相互的神经支配。为了进一步探讨这两个递质系统在唇针镇痛中的作用,我们用生理学方法,以不同的组合方式损毁和/或刺激中缝背核和蓝斑,观察其对唇针镇痛的影响.

NUCLEUS RAPHE DORSALIS,LOCUS COERULEUS AND LIP-ACUPUNCTURE ANALGESIA

It has been demonstrated in our laboratory thatraphe serotonergic neu- ronal system plays an important role in lip-acupuncture analgesia(LAA), Midbrain raphe lesion or pCPA administration could decrease LAA;on the contrary,raphe stimulation or 5-HT intraventricular injection resulted in enhancement of LAA.There are also evidences that coerulo-noradrenergic neuronal system can affect acupuncture analgesia.Furthermore,recently it has been known that reciprocal innervations exist between raphe dorsalis (RD)and locus coeruleus(LC).In this communication the interaction between RD and LCin lip-acupuncture analgesia was studied in rats by lesion and/or stimulation of these nuclei in various combinations. Methods of lip-acupuncture,pain threshold measurement,brain lesion and brain stimulation have been described previously(Zhonghua Yixue Zazhi, 1979,59(9):534-538). 1.Bilateral LC iesion+RD stimulation: LAA was decreased 3 days after LC lesion(from prelesion value 138% to 84%)and increased significantly to 221%(P<0.01)by subsequent RD stimulation. 2.RD lesion+unilateral LC stimulation: Seven days after RD lesion LAA was decreased significantly(P<0.01) from prelesion value 317% to 97%,and increased to 143% by subsequent LC stimulation. 3.Bilateral LC lesion+RD lesion simultaneously: Three and Seven days after simultaneous lesions of these nuclei LAA was decreased significantly from prelesion value 277% to 146%(P<0.05)and 97% (P<0.01)respectively. 4.RD lesion followed by bilateral LC lesion: Three days after RD lesion LAA was decreased significantly(P<0.05) from prelesion value 237% to 51%.No further significant effect on LAA was obser red after the following LC lesion(107%). 5.Bilateral LC lesion followed by RD lesion: Three days after LC lesion LAA was decreased significantly(P<0.05) from prelesion value 168% to 81%.No further significant effect on LAA was observed after the following RD lesion(29%). There were no significant variations in LAA in corresponding sham-opera- ted control groups. From the above-mentioned experiments it is evident that LAA decreases after RD or LC lesion,and increases after RD or LC stimulatlon,and that no reciprocal antagonistic interaction exists between these nuclei in LAA.It is suggested that lip-acupuncture may activate both descending raphe-spinal serotonergic and coerulo-spinal noradrenergic systems which,in turn,inhibit nociceptive neurotransmission at spinal level.The possibilities of the effects of ascending projections from these two nuclei on pain-integrating function at higher centers,and of the involvement of enkephalin in LAA can not be excluded.