[Changes of norepinephrine release in rat's nucleus reticularis paragigantocellularis lateralis in acupuncture...

Norepinephrine (NE) of the nucleus reticularis paragigantocellularis lateralis (RPGL) plays an important role in acupuncture analgesia (AA). The aim of this experiment was to investigate the role of NE in RPGL during AA at presynaptic level by using push-pull perfusion, high performance liquid chromatography with electrochemical detection (HPLC-ECD) techniques. The results indicated that pain threshold increased significantly after 20 min of EA, while the content of NE and its metabolite MHPG in the perfusate from the RPGL was markedly decreased. A negative correlation existed between the changes of pain threshold and the release of NE and MHPG. It is indicated that electroacupuncture (EA) is able to inhibit the release of NE from the RPGL during AA.