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以往的研究表明外周热伤害性感受器辣椒素受体 1(VR1,也称为 TRPV1)在热伤害性感觉中发挥着重要作用 ,但是脊髓 VR1在其中扮演的角色尚不清楚。因此本实验利用老龄大鼠蜜蜂毒 (BV)模型热痛敏 (仅持续 2 4h)和机械性痛敏 (持续 1月以上 )时程分离的行为学特点研究了在老龄大鼠中脊髓 VR1在外周组织损伤和炎性痛状态下的热敏感性中扮演的角色。在 BV注射后 4h(即热痛敏和机械性痛敏均存在时 )、2周 (即热痛敏消失而机械性痛敏存在时 )和 2月 (即两种痛敏均消失时 ) ,验证了热敏感性 (辐射热刺激 )和机械敏感性 (von-Frey纤维刺激 ) ,随后进行脊髓背角的 VR1免疫组织化学染色。结果如下 :(1)在未处理老龄大鼠组 ,VR1样免疫反应产物 (L I)在脊髓背角主要分布于 I、II层 ;(2 )在经 BV处理老龄大鼠组 ,外周损伤后 4h脊髓背角 VR1-L I有轻微增加 ,但在 2周后 VR1-LI表达水平明显低于对照水平 ,而且在 BV注射 2月后 ,即两种痛敏均消失时 ,VR1-L I表达水平下调仍非常明显。本结果表明脊髓背角的 VR1在空间分布上不随年龄改变而改变 ,但在周围化学组织损伤或炎症状态下 ,VR1-LI的表达水平可能与热敏感性的变化有动态相关性。由此我们提出除了外周位点 ,脊髓背角的 VR1也可能参与了热痛阈水平的维持和热痛敏的产生
Previous studies have shown that the peripheral thermal nociceptin capsaicin receptor 1 (VR1, also known as TRPV1) plays an important role in thermal nociception, but the role of spinal cord VR1 in this role remains unclear. Therefore, in this experiment, the behavioral characteristics of the time-course separation of thermo-sensitization (lasting 24 h) and mechanical hyperalgesia (lasting for more than 1 month) in bee venom model of aged rats Peripheral tissue damage and the role of heat-sensitivity in inflammatory pain states. At 4 hours after BV injection (ie, thermal pain and mechanical allodynia were present), 2 weeks (ie, when the thermal pain disappeared with mechanical pain sensitivity) and 2 months (ie, both pain sensitivities disappeared), validation Thermal sensitivity (radiant heat stimulation) and mechanical sensitivity (von-Frey fiber stimulation) were followed by VR1 immunohistochemical staining of the dorsal horn of the spinal cord. The results were as follows: (1) In the untreated aged rats, the VR1-like immunoreactive product (LI) mainly distributed in the spinal dorsal horn in layers I and II; (2) In BV group, The level of VR1-LI in spinal dorsal horn increased slightly, but the level of VR1-LI was significantly lower than that of control after two weeks, and the expression of VR1-LI was still decreased after two months of BV injection very obvious. The results suggest that the spatial distribution of VR1 in spinal dorsal horn does not change with age, but the expression level of VR1-LI may be dynamically related to the change of thermosensitivity in the surrounding chemical tissue injury or inflammation. From this we propose that in addition to peripheral sites, VR1 in the dorsal horn of the spinal cord may also be involved in the maintenance of thermal pain threshold levels and the generation of thermal hyperalgesia