大鼠中枢P物质含量与针刺镇痛的关系

<正> 已知 P 物质(SP)在痛觉调制中,具有双重作用:鞘内注射 SP 拮抗剂可对抗 SP 引起的痛阈下降,将 SP 注入脑室、中脑导水管周围灰质,可出现镇痛作用。其镇痛效应可能是通过释放脑啡肽而实现的。以往的研究多应用脑室(或中脑导水管周围灰质),腹腔、肌肉以及鞘内注射或微电泳导入 SP 或 SP 抗体等方法,观察痛阈及神经元电位的变化。但在电针时,动物不同脑区和脊髓 SP 含量的变化有何不同,已有报道。为了进一步探讨中枢 P 物质与针刺镇痛的关系,本工作从三个方面进行观察:一是电针时大鼠海马、下丘脑、纹状体和脊髓内SP 免疫活动物质(Ir-SP)含量的变化;二是电针强度和频率对 Ir-SP 含量的影响;同时还观察了阿片受体和5-羟色胺(5-HT)受体在电针引起不同脑区 Ir-SP 含量变化中的作用。

Relationship between the content of central substance P and the analgesic effect of electroacupuncture in rats

Substance P(SP) immunoreactivity in the rat brain and spinal cord were measured by radioimmunoassay and studied to correlate with the analgesic effect induced by electroacupuncture (EA). The results showed following: (1) There was a significant elevation in SP levels sn the hippocampus, hypothalamus and striatum after 30 min of EA. There was a markedly fall in the spinal cord. Statistical analysis revealed a positive correlation between the EA effect and the SP content in hypothalamus, striatum and statistical analysis revealed a correlation. In the spinal cord. (p less than 0.01), while the SP content in the hippocampus exhibited a similar degree of elevation in non responsive and good responsive animals to EA stimulation. (2) SP levels in the hippocampus, hypothalamus and striatum were increased by electroacupuncture stimulation (3v). The frequency of 1.5Hz was no obvious difference as compared with 100Hz in the effects on brain SP content. (3) SP content in the spinal cord decreased only using electroacupuncture stimulations of combination of higher intensity (3v) and higher frequency (100 Hz). (4) This effect could be blocked by the naloxone (i.p) and LSD (icv), but icv injection of Met-enkephalin antibodies had no affects on them.