癫痫发作敏感大鼠T区κ型阿片受体和NR_(2B)表达变化

THE CHANGE OF K OPIOID RECEPTORS AND NR_(2B) IMMUNOREACTIVITY IN AREA TEMPESTAS OF SEIZURE SENSITIVE RATS

为探讨前深梨状皮层T区(AT)κ型阿片受体与N-甲基-D-天门冬氨酸受体2B亚型(NR2B)表达在红藻氨酸(KA)诱导的癫痫发作敏感性长期增强中的作用。本研究采用颗叶癫痫(KA)模型,制备癫痫发作敏感大鼠,以免疫组化方法检测前深梨状皮层T区κ型阿片受体与NR2B表达变化,并结合行为学观察,与经蝎毒处理后癫痫发作敏感性明显降低的大鼠进行比较。结果显示,与对照组比较,癫痫发作敏感动物前深梨状皮层T区κ型阿片受体与NR2B免疫反应阳性细胞数目均明显减少,染色强度明显降低(P<0.05),以剂量为100 mg／(kg·d)的蝎毒(SV)给予动物连续灌胃4周,可明显降低其癫痫发作敏感性(P<0.05),丽脑内前深梨状皮层T区κ型阿片受体与NR2B免疫反应活性未见明显变化。以上结果提示:前深梨状皮层T区κ型受体免疫反应活性长期降低很可能是癫痫发作敏感性长期增强的重要原因之一,而NR2B免疫反应活性长期降低可能是一种对脑内神经元过度兴奋的代偿性内源性保护机制。

To investigate the role of κopioid receptors and NR2B in the long-lasting enhancement in seizure susceptibility induced by kainic acid (KA), the relationship between the change of expression of K opioid receptor and NR2B in Area tempetas (AT) and the long-lasting enhancement of seizure susceptibility was investigated by immunocytochemistry and observing the behavior of rats treated with scorpion venom (SV) and normal saline(NS) for four weeks respectively. Compared with the control group (NS+NS group), the density of K opioid receptor-IR and NR2B-IR. the number of K opioid receptor-IR and NRzB-IR positive neurons in AT and the degree of epileptic seizures were remarkably decreased in seizure sensitive rats (P<0. 05) , but those of KA+SV group had no change (P>0. 05). The long-lasting decrease of K opioid receptor-IR in AT may be one of the important factors for the long-lasting enhancement in seizure susceptibility, while the down-regulation of NR2B-IR may represent anen-dogenous compensatory protective reaction against hyperexcitability in brain.