大鼠三叉神经节及尾侧亚核内PPTA mRNA在伤害性刺激条件下的时程变化

NOXIOUS STIMULATION INDUCES PREPROTACHYKININ A mRNA EXPRESSION IN THE NEURONS OF THE TRIGEMINAL GANGLION AND CAUDAL SPINAL TRIGEMINAL NUCLEUS IN THE RAT

将福尔马林注入大鼠一侧口周皮下，用原位杂交法观察三叉神经节和三叉神经脊束核尾侧亚核内PPTAmRNA表达的时程变化。证明：PPTAmRNA在三叉神经节内的表达于刺激后4h有明显增加，24h达到高峰，48h后恢复至正常；在尾侧亚核中，PPTAmRNA的表达及变化主要限于Ⅰ、Ⅱ层，其时程变化与在三叉神经节中的变化相似。PPTAmRNA表达的增加仅出现于刺激侧的三叉神经节和尾侧亚核，而对侧和对照组则无明显变化。提示伤害性刺激可直接或跨突触增强尾侧亚核PPTAmRNA的表达，意味着PPTA在西口部伤害性信息的传递和调控中起重要作用。

Increased preprotachykinin A (PPTA) mRNA expression in the neurons of the trigerninal ganglion (TG) and su-perficia] layers of the caudal spinal trigeminal nucleu5 (Vc) induced by peripheraI noxious stirnulation were exarnined by insitu hybridixiltion histochemistry. Forrnalin was used aS a noxious stimulus in which a srnall arnount of formalin was subcuta-neously injected into the right perioraI region of the upper lip lateral to tl1e nose. After forma]in injectlon, 1he rats werekilled at different time point. The changes of PPTA tnRNA expression were found lu result in a significant increase in thenumber of neurons expressing PPTA rnRNA in the ipsilateral TG and superficial layers of the Vc. Expressions of PPTAmRNA were increasing in neuJ ons of TG and Vc from 4 h to 24 h, and graduIly decreased to normal levels by 48 h afterstimulation. The number of PPTA mRYA expression neurons was almost not affected by the formalin injection in the TG andVc on the contralateral side and in cbntroI animaIs. Tl1e present reslllts sl1owed that noxious stimulation can directly or transsynapticIly activate biosynthesis of PPTA mRNA in the TG or Vc and indicated that PPTA might play important rols in thetransmission and regulation of noxious stimulation information.