NMDA Receptor Phosphorylation and Trafficking after Pain

描述(申请人提供)：中枢敏感化，一种由C-传入输入产生的背角神经元兴奋性的活动依赖性增加，被认为是导致病理性疼痛状态产生的主要机制。脊髓背角N-甲基-D-天冬氨酸(NMDA)受体活性增强与中枢敏感化的发生有关。这一建议的中心假设是，外周伤害性信息输入可以导致中枢敏化，至少部分是通过改变背角NMDA受体的磷酸化和细胞内运输。 本研究的目的是研究中枢敏化产生过程中背角NMDA受体亚单位磷酸化和亚细胞分布的变化。此外，这些伤害性刺激诱导的NMDA受体亚单位改变所涉及的细胞内信号通路将被研究并与疼痛行为相关联。 这些实验将检验几个具体的假设：1)足以产生中枢敏化的外周伤害性刺激改变了脊髓背角神经元中NMDA受体亚单位的磷酸化。2)足以产生中枢敏化的外周伤害性刺激改变了脊髓背角神经元的NMDA受体亚单位转运。3)外周伤害性刺激引起的NMDA受体亚单位磷酸化和转运的改变与中枢敏化的行为指标存在时间上的相关性。 尽管翻译后NMDA受体的变化被认为是中枢敏化基础上的突触可塑性的关键，但对这一假说的体内直接研究很少。背角神经元中NMDA受体的磷酸化和运输，从细胞内储存到突触后部位，都将被研究，因为它们与中枢性疼痛过敏有关。

DESCRIPTION (provided by applicant): Central sensitization, an activity-dependent increase in the excitability of dorsal horn neurons generated by C-afferent input, is thought to be a primary mechanism responsible for the generation of pathological pain states. Enhanced activity of spinal cord dorsal horn N-methyl-D-aspartate (NMDA) receptors has been implicated in the development of central sensitization. The central hypothesis of this proposal is that peripheral nociceptive input can lead to central sensitization at least in part through altered phosphorylation and intracellular trafficking of dorsal horn NMDA receptors. The aim of this proposal is to examine changes in dorsal horn NMDA receptor subunit phosphorylation and subcellular distribution during the generation of central sensitization. In addition, intracellular signaling pathways involved in these noxious stimulus-induced NMDA receptor subunit changes will be investigated and correlated with pain behaviors. The proposed experiments will test several specific hypotheses: 1) Peripheral noxious stimulation sufficient to generate central sensitization alters NMDA receptor subunit phosphorylation in spinal cord dorsal horn neurons. 2) Peripheral noxious stimulation sufficient to generate central sensitization alters NMDA receptor subunit trafficking in spinal cord dorsal horn neurons. 3) Peripheral noxious stimulation induced changes in NMDA receptor subunit phosphorylation and trafficking are temporally related to behavioral measures of central sensitization. Although post-translational changes in the NMDA receptor are believed critical for the synaptic plasticity that underlies central sensitization, there has been little direct in vivo investigation of the hypothesis. Both phosphorylation and trafficking, from intracellular stores to the postsynaptic site, of NMDA receptors in dorsal horn neurons will be investigated as they relate to central pain hypersensitivity .