吗啡和电针对脊髓内P物质的影响及其与痛阈的关系

腹腔注射吗啡(7.5mg/kg)或电针“夹脊”穴(3V,3Hz)均可使痛阈明显升高,脊髓内P物质样免疫活性物质(Ir-SP)含量及脊髓背角P物质样免疫反应物(SP-LI)显著增多(P<0.05～0.01)。腹腔注射吗啡加电针刺激,上述效应更为显著(P<0.01)。纳洛酮可阻断吗啡及电针所引起的痛阈升高和脊髓内Ir-SP含量增多的效应。结果提示:吗啡与电针的镇痛效应可能与经阿片受体为介导的脊髓内P物质增多有关。吗啡和电针对此具有协同作用。

Effects of Morphine and Electroacupuncture on Substance P Level in Spinal Cord and Their Relation to Pain Threshold in Rats

Immunoreactive substance P (Ir-SP) level and substance P-like activity (SP-LI)in the spinal cord were determined with radioimmunoassay and immunohistochemistry in rats after they were given an intraperitoneal injection of morphine(7.5mg/kg)or electroacupunctured(3V and 3Hz)on the "Jiaji" point. It was found that pain threshold,Ir-SP content,and SP-LI activity in the dorsal horn of the spinal cord were significantly increased in the experimental group than in the control (P<0.05-0.01) . The above mentioned effects were more marked when morphine injection and electroacupuncture were used combinedly than either of them was used signly,and they could be prevented from occurring when naloxane was administered.Our results suggest that there is a synergism between morphine and electro-acupuncture and the analgesic effect of morphine and electroacupuncture is related to the increase of Ir-SP content of the spinal cord mediated through opiate receptors.