TRPV4对SP和CGRP的作用及在神经病性疼痛的机制研究

Neuropathic pain have complex mechanisms and unclear reasons .TRPV4 is a non-selective Ca2 + channel in recent years, is believed to play an important role in the occurrence of neuropathic pain, but the mechanism has not been fully elucidated.Chronic compression of the dorsal root ganglion (DRG) (the procedure hereafter termed CCD) in animals, a typical model of neuropathic pain, mimics clinical disc herniation and spinal canal stenosis in humans. CCD rats show ipsilateral spontaneous pain, mechanical allodynia, and thermal hyperalgesia. In association with these behavioral effects, an increased excitability of neuronal somata in the compressed ganglion has been shown, as evidenced by spontaneous activity, lowered rheobase and action potential thresholds. However, to date, the detailed mechanisms remain unclear. Our results showed TRPV4 was involved in thermal hyperalgesia in CCD rats via Ca2+-nNOS pathway. Substance P (SP) and calcitonin gene-related peptide (CGRP), both are well-known pain-related neuropeptide, have the role to excite neurons, participate in the transmission of nociceptive signals and contribute to mechanical and thermal hyperalgesia. It is reported that SP and CGRP are regulated by Ca2+ and nNOS. Therefore, we propose the hypothesis: TRPV4 regulate the over-expression of SP and CGRP, excite neurons and contribute to hyperalgesia following the CCD. To test this hypothesis, we will apply the animal models and cell cultures, using behavioral, real time PCR, western blot, Si RNA interference, blocking specific receptors and patch clamp and other means, from the molecular, cellular, tissue and animal level of disease for verifying the effect of TRPV4 on SP and CGRP, and elucidating the mechanisms of this. To futher make it clear that SP and CGRP are the molecular basis of TRPV4-mediated neuron excitability. The theoretical and experimental basis is useful for the treatment of neuropathic pain.

神经病性疼痛机制复杂，原因不清。TRPV4是一种非选择性Ca2+通道，近年来被认为在神经病性疼痛的发生中具有重要作用，其机制尚未完全阐明。我们前期实验结果显示TRPV4可能通过 Ca2+-nNOS参与慢性压迫背根神经节（CCD）大鼠的痛敏。P物质（SP）和降钙素基因相关肽（CGRP），均有兴奋神经元，介导痛敏的作用，且受Ca2+、nNOS调控。因此我们提出假说：CCD后TRPV4可能通过Ca2+-nNOS调控SP、CGRP过表达，兴奋神经元，引起痛敏。为了验证这一假说，我们将通过动物模型和细胞培养，采用行为学、RT-PCR、ELISA、siRNA干扰、受体特异阻断和膜片钳等手段，从分子、细胞、组织及动物等层次验证神经病性疼痛状态下TRPV4对SP、CGRP的作用及机制，并明确SP、CGRP是TRPV4介导的神经元高兴奋性的分子基础，为神经病性疼痛的发生机制奠定基础，为其治疗提供新思路。

神经病性疼痛机制复杂，原因不清。TRPV4是一种非选择性Ca2+通道，近年来被认为在神 经病性疼痛的发生中具有重要作用，其机制尚未完全阐明。我们前期实验结果显示TRPV4 可能通过 Ca2+-nNOS参与慢性压迫背根神经节（CCD）大鼠的痛敏。P物质（SP）和降钙素 基因相关肽（CGRP），均有兴奋神经元，介导痛敏的作用，且受Ca2+、nNOS调控。我们通过动物模型和细胞培养，采用行为学、RT-PCR、ELISA 、siRNA干扰、受体特异阻断和膜片钳等手段，从分子、细胞、组织及动物等层次证实： 神经病性疼痛状态下（CCD）TRPV4通过Ca2+-nNOS调控SP、CGRP过表达，兴奋神经元，引起痛敏。并明确SP、CGRP是TRPV4介导的神经元高兴奋性的分子基础，为神经病性疼痛的发生机制奠定基础，为其治疗提供新思路。