摘要
The effects of single or repeated electroconvulsive shocks (ECS) on the abundance of mRNAs coding for prodynorphin (DYNmRNA) and proenkephalin (EK mRNA) in rat brain were investigated. Rats were given either a single ECS and sacrificed at 0.5, 2, 6, or 12 h post-shock (expt. I), or were subjected to ECS for 1, 3 or 6 days and killed 24 h after the last shock (expt. II). The amounts of DYN mRNA and EK mRNA were measured in several brain regions using RNA blot analysis. In expt. I, a biphasic change in the DYN mRNA level was found in the hippocampus, with an initial 49% decrease at 0.5 h followed by a 51% increase at 6 h after a single ECS. The EK mRNA content in the entorhinal cortex started to increase at 0.5 h, and continued to rise, reaching 260% of the control level at 12 h post-shock. A smaller increase in the EK mRNA level was found also in the hippocampus at 2 to 12 h post-shock. No significant increase in [Met5]-enkephalin or dynorphin A(1–8) immunoreactivity was detected by radioimmunoassay in either area. In expt. II, a dramatic reduction in the DYN mRNA level was observed in the hippocampus 24 h after a single or repeated ECS. In contrast, elevated DYN mRNA levels were seen in the striatum and hypothalamus. The EK mRNA level remained elevated in the entorhinal cortex after 6 daily ECS. These data indicate that in the entorhinal cortex-hippocampal region, a single ECS rapidly triggered a transient increase in the biosynthesis of both dynorphin and enkephalin within 12 h, and then decreased dynorphin expression was found 24 h post-shock; repeated ECS further reduced dynorphin mRNA level but increased that of enkephalin. The differential regulation of these two opioids may play an important role in the modulation of the excitability of the hippocampus during recurrent seizures.
摘要译文
研究了单次或重复电惊厥休克（ECS）对编码大鼠脑中前体啡肽（DYNmRNA）和脑啡肽（EK mRNA）的mRNA丰度的影响。给予大鼠单次ECS并在休克后0.5,2,6或12小时处死（expt。 I），或经受ECS 1,3或6天，并在最后一次休克后24小时死亡（expt。 II）。使用RNA印迹分析在几个脑区域中测量DYN mRNA和EK mRNA的量。在expt。 I，在海马中发现DYN mRNA水平的双相变化，在0.5小时后最初49％减少，然后在单个ECS后6小时增加51％。内嗅皮质中的EK mRNA含量在0.5小时开始增加，并且持续升高，在休克后12小时达到对照水平的260％。在休克后2至12小时，海马体中也发现EK mRNA水平的较小增加。 [Met 5 ]没有显着增加 - 在任一区域通过放射免疫测定检测到脑啡肽或强啡肽A（1-8）免疫反应性。在expt。 II，在单次或重复ECS后24小时，在海马中观察到DYN mRNA水平的显着降低。相反，在纹状体和下丘脑中观察到升高的DYN mRNA水平。在每日6次ECS后，内嗅皮质中的EK mRNA水平仍然升高。这些数据表明，在内嗅皮质 - 海马区域，单个ECS在12小时内迅速触发强啡肽和脑啡肽生物合成的短暂增加，然后在休克后24小时发现强啡肽表达减少;重复的ECS进一步降低了强啡肽mRNA水平，但增加了脑啡肽的水平。这两种阿片类药物的差异调节可能在复发性癫痫发作期间调节海马的兴奋性中起重要作用。
C.W.Xie[1];P.H.K.Lee[1];K.Takeuchi[1];V.Owyang[1];S.J.Li[1];J.Douglass[2];J.S.Hong[1];. Single or repeated electroconvulsive shocks alter the levels of prodynorphin and proenkephalin mRNAs in rat brain[J]. Molecular Brain Research, 1989,6(1): 11-19