This experiment was carried out on 35 rats with stereotaxic apparatus following a new coordinate which was designed by ourselves. The microelectrode was pushed into the lateral dorsal raphe nucleus (LDR) under direct vision. The neurons with regular rhythm and slow firing rate were searched by intracellular recording, then the singular cell in LDR was filled with HRP by intracellular iontophoresis.
Results: 7 HRP labelling neurons with serotoninergic firing characteristics were observed in LDR. The labelling dendrites were found in neighboured structure (periaqueductal gray, laterodorsal tegmental nucleus, dorsal tegmental nucleus, 4th ventricle). This work demonstrated that LDR plays some role in acupuncture analgesia.