MOLECULAR MECHANISM OF ABNORMAL SENSATION AFTER INJURY OF INFERIOR ALVEOLAR NERVE

P2 X3受体是一种配体门控阳离子通道，通过与细胞外腺苷5 '-三磷酸（ATP）结合而激活，ATP是一种被认为在组织和神经损伤后的伤害性通路中发挥作用的物质。在周围神经损伤后，已经观察到感觉神经节神经元中P2 X3受体的下调和上调。为探讨神经损伤后初级感觉神经元P2 X3 mRNA表达的精确调控，采用大鼠胫神经、腓总神经和眶下神经两种神经损伤模型，分别观察背根神经节（DRG）和三叉神经节神经元P2 X3 mRNA的表达。两个神经元群体中的P2 X3 mRNA通过与寡核苷酸探针的原位杂交检测，所述寡核苷酸探针通过北方印迹分析确认。为了鉴定轴突切断的神经元，我们检测了转录激活因子3（ATF 3）的表达， ...更多信息 在DRG中，P2 X3 mRNA标记的神经元相对于神经元总数的平均百分比从未处理大鼠的32.7%增加到损伤后3天的42.7%。伤后28天逐渐下降至11.2%。在三叉神经节，P2 X3 mRNA标记的神经元的平均百分比为36.9%，在损伤后3天，与26.0%的幼稚大鼠。在损伤后1天，P2 X3 mRNA阳性神经元的平均阳性率为25.3%，28天下降到6.1%，损伤后P2 X3 mRNA阳性神经元的阳性率明显下降，说明切断轴突后，P2 X3 mRNA的表达减少，尽管P2 X3 mRNA相对于感觉神经节神经元总数增加。这些数据有力地表明，完整的神经元中P2 X3 mRNA的表达增加，完整的神经元中的P2 X3 mRNA可能在初级感觉神经元的神经损伤后的病理机制中发挥作用。少

The P2X3 receptor is a ligand-gated cation channel activated by the binding of extracellular adenosine 5'-triphosphate (ATP), an agent that has been suggested to have a role in the nociceptive pathway after tissue and nerve injury. After peripheral nerve injury, both down regulation and up regulation of the P2X3 receptor in sensory ganglion neurons have been observed. The purpose of this study was t examine the precise regulation of P2X3 mRNA expression in primary sensory neurons after nerve injury.We used two nerve injury models in the rat, the transection of the tibial and common peroneal nerves and the transection of the infraorbital nerve, and observed dorsal root ganglion (DRG) and trigeminal ganglion neurons, respectively. P2X3 mRNA in both neuron populations was detected by in situ hybridization with an oligonucleotide probe that was confirmed by Northern blot analysis. To identify axotomized neurons, we examined the expression of activating transcription factor 3 (ATF3), which … More is regarded as a neuronal-injury marker, using immunohistochemistry.In the DRG, the mean percentage of P2X3 mRNA-labeled neurons relative to the total number of neurons increased from 32.7% in the naive rats to 42.7% at 3 days after injury The mean percentage of P2X3 mRNA-labeled neurons in ATF3 immunoreactive (ir) neurons was 29.5% at 3 postoperative days, which gradually decreased to 11.2% at 28 days after injury. In the trigeminal ganglion, the mean percentage of P2X3 mRNA-labeled neurons was 36.9% at 3 days after injury, versus 26.0% in the naive rats. In the ATF3-ir neurons, the mean percentage of P2X3 mRNA-labeled neurons was 25.3% at 1 postoperative day and was reduced to 6.1% at 28 postoperativ days.The finding that P2X3 mRNA in ATF3-ir neurons decreased significantly after injury indicates that axotomized neurons decreased the expression of P2X3 mRNA, despite the increase in P2X3 mRNA relative to the total number of sensory ganglio neurons. These data strongly suggest that P2X3 mRNA expression increases in intact neurons and that P2X3 mRNA in intact neurons may play a role in the pathomechanism of post nerve injury in primary sensory neurons. Less