楔状核内促甲状腺素释放激素抗伤害感受机制的探讨

INVESTIGATION OF THE MECHANISM OF THE ANTINOCICEPTIVE ROLE OF THYROTROPIN-RELEASING HORMONE IN NUCLEUS CUNEIFORMIS

目的 :探讨楔状核 (NCF)内促甲状腺素释放激素 (TRH )抗伤害感受作用的机制。方法 :用玻璃微电极细胞外记录结合核团微量注射的方法 ,于延髓中缝大核 (NRM )内记录痛兴奋神经元(PEN)的单位放电 ,观察中脑导水管灰质 (PAG )内注射纳络酮对NCF内注射TRH引起的NRM内PEN的痛放电变化的影响。结果 :PAG内预先注射纳洛酮 (1μg/ 0 .5 μl)能部分阻断NCF内TRH对NRM内PEN痛放电的抑制效应。结论 :TRH在NCF内的抗伤害感受作用可能通过下行镇痛通路实现 ,与PAG内的阿片受体有关。

Object: To investigate the mechanism of the antinociceptive role of thyrotropin releasing hormone (TRH) in nucleus cuneiformis (NCF). Methods: Using extracellular recording technique together with microinjection of drugs into nuclei ,we recorded the frequencies of evoked dicharge of pain excitation neurons (PEN) in nucleus raphe magnus (NRM) to investigate the mechanism of the antinociceptive role of TRH in NCF. Results: Intra NCF injection of TRH (0.5μg/ 0.5μl) could lower the frequency of evoked discharge of PEN in NRM ( P <0.001,0.05), the maximal inhibitory rate being 71.2%±5.9%. Intra PAG preinjection of naloxone (1μg/0.5μl,n=9)could partially antagonise the effect of intra NCF of TRH on the frequency of evoked discharge of PEN in NRM. Conclusion: Some neurons in NCF might participate in the modulation of noxious information transmission in CNS;TRH might be a neuromodulator or transmitter in the antinociception of NCF and its effect may be mediated by opioid receptor in PAG.