In order to provide foundation for explaining the mechanism of the analgesic effect elicited by stimulation of septa which is mediated via habenular nuclei

the afferent connections of NOS positive neurons of habenular nuclei from the septal area were studied by combined method of horseradish peroxidase(HRP) and nicotinamide adenosine dinucleotide phosphate diaphorase (NADPH-d) in rats. The results showed that the lateral habenular nucleus received the prOections of NOS PoSitive neurons from the ventral part of vertical limb of diagonal band nucleus(VDB)

the horizontal limb of diagonal band nucleus(HDB) and the dorsal part of VDB

that the medial habenular nucleus received a few proections of NOS positive neurons from the ventral part of VDB. It is possible that the fiber connections of NOS positive neurons between septal area and habenular nuclei are one of their important morphological basis for acupuncture analgesia.