甲啡肽、纳络酮对红藻氨酸、谷氨酸在大鼠海马兴奋作用的调制

The modulation of met-enkephalin and naloxone on the excitatory effects of kainic acid and glutamic acid in hippocampus of rats

目的 研究甲啡肽、纳络酮对红藻氨酸、谷氨酸在大鼠海马兴奋作用的调制 ,探讨甲啡肽、纳络酮影响癫疒间生的可能机制。方法 健康Wistar大鼠以 1%戊巴比妥钠 (3ml kg)腹腔注射麻醉后行气管插管并固定于立体定位仪上 ,清醒后用 0 .0 1%d 筒箭毒 (1mg kg)腹腔注射制动。使用多管微电极微电泳给药并细胞外记录海马单位放电。结果 ①甲啡肽可兴奋大多数海马神经元 ,阿片受体拮抗剂纳络酮可拮抗甲啡肽的上述作用。而纳络酮单独电泳对海马神经元放电频率无影响。②红藻氨酸、谷氨酸可强烈兴奋海马神经元 ,甲啡肽及纳络酮可以影响这种兴奋作用。结论 甲啡肽可能通过调节红藻氨酸、谷氨酸在海马的兴奋作用来影响癫疒间 的发生。

Objective To observe the modulation of met enkephalin (ME) and naloxone (NLX) on the excitatory effects of kainic acid (KA) and glutamic acid (GLU) in hippocampus of rats and to explore the possible mechanism of the effects of ME in the KA epilepsy model. Methods A total of 45 healthy Wistar rats were anesthetized with 1% sodium pentobarbital (3 ml/kg intraperitoneal injection). After endotracheal intubation, the animal was mounted onto a SN 1stereotaxic apparatus (Narishige) and routine craniotomy was performed. Then the animal was immobilized by 0.01% curare (1 mg/kg) after it woke up. The peripheral pipettes of a multiple pipette microelectrode were used for microelectrophoretic application of drugs; the central pipette was used for extracellular recording of the hippocampal unit discharges (HUDs). Results ①ME excited most of the HUDs; opioid receptor antagonist NLX could reverse the excitatory effects of met enkephalin. NLX applied alone had no effects on the firing rate of HUDs. ②KA and GLU excited the HUDs intensively but ME and NLX could modulate their excitatory effects. Conclusion ME may promote the development of epilepsy by modulating the excitatory effects of KA and GLU in hippocampus.