反复发热惊厥大鼠脑内NOS/NO体系的变化

目的研究一氧化氮合酶(NOS)，一氧化氮(NO)体系与反复发热惊厥(febrile seizures，FS)的关系。方法采用热水浴诱导大鼠FS，隔日1次，每次大鼠进行热水浴的时间不超过5min，共10次。大鼠随机分为2组：正常对照组和发热组，后者又根据惊厥与否进一步分为发热对照组和反复FS组。用原位杂交法观察大脑皮层神经元型NOS(nNOS)mRNA的变化，用分光光度计检测大鼠脑组织及血浆中NO含量，用放射免疫法检测大鼠脑组织cGMP含量。结果在大脑皮层深层，FS组nNOS表达阳性的神经元明显增高，而发热对照组仅出现少量nNOS阳性神经元，正常对照组偶见nNOS阳性神经元；脑组织及血浆中NO含量各组间无统计学意义；FS组脑组织cGMP含量吸显高于正常对照组及高热对照组。结论大鼠反复FS后24h脑内nNOS mRNA表达增高，但此时NO不见增多，脑组织cGMP水平增高，可能由于其他途径调节所致。

Changes of nitric oxide synthase/nitric oxide system in the brain of rats with recurrent febrile seizures

ObjectiveTo study the relationship of nitricoxide synthase (NOS)/nitric oxide (NO) system and recurrent febrile seizures (FS). MethodsFS in rats was induced ten times, once every 2 days. In a bath of warm water, developing rats were randomly divided into two groups: control group and warm water-treated group. The latter was further divided into hyperthermia group and FS group. The expression of neuronal NOS (nNOS) mRNA was observed in cortex of rats used in situ hybridization. The concentration of NO in brain and plasma was detected by the spectrophotometer. The concentration of cGMP in brain was detected by radioimmunoassay. ResultsInduced nNOS-positive neurons were significantly increased in deep layer of the cortex in FS group, while few nNOS-positive neurons were observed in hyperthermia group and only constitutive nNOS-positive neurons were observed in control group. There was no significant difference in NO concentration in brain and plasma among the three groups. cGMP concentration significantly increased in FS group as compared with those in hyperthermia group and control group. Conclusion Recurrent FS in rats could cause the increase of nNOS mRNA expression in brain at 24h after the last FS but the level of NO did not increase. cGMP concentration increase in brain tissue may be induced by other pathway.