Signal transdaction and gene expression in the pors associated with the overactive bladder following cerebra-vascular disease

目的：探讨脑梗塞后脑桥被盖区(PTA)与膀胱过度活动的信号转导及分子机制。方法：采用左侧大脑中动脉闭塞(MCAO)法制备SD大鼠脑梗塞模型。用持续输注膀胱术监测清醒大鼠的膀胱活动。观察H-89(蛋白激酶A抑制剂)、放线菌素D(ACD；RNA合成抑制剂)或NS-398(COX-2抑制剂)对膀胱活性及c-fos和Zif268基因表达的影响。实时定量聚合酶链式反应检测DPT中c-fos和Zif268基因的表达。结果：脑梗塞(CI)大鼠在MCAO后膀胱容量(BC)显著减少，并持续低于阻断前容量的一半。H-89在MCAO后2小时给药，可抑制Bc的降低。ACD还可阻断CI大鼠血脑屏障的降低。在急性脑梗塞大鼠中，BC逐渐恢复…并在10小时内恢复到大脑中动脉阻塞前的控制水平。MCAO前应用NS-398可剂量依赖性地阻止膀胱过度活动的发生，但对脑梗塞体积无明显影响。与假手术组相比，MCAO后1h、3h，Zif268基因的表达明显增强。预先给予谷氨酸能NMDA受体拮抗剂MK-801可抑制膀胱过度活动的形成，并显著降低PTA中这些基因的表达。ACD可抑制大脑中动脉结扎后1h和3h后Zif268中c-fos基因表达的增加。结论：MCAO后膀胱过度活动的发生与NMDA受体的激活和RNA的合成有关。研究发现，DPT中的转录对于维持脑梗塞引起的长期膀胱过度活动是必要的。此外，大脑中的COX-2分子机制似乎与膀胱过度活动有关。进一步研究大脑中与膀胱过度活动有关的分子机制可能会导致针对排尿中心的药物治疗。较少

Object: To investigate the signal transduction and molecular mechanisms in the pontine tegmental area (PTA) associated with bladder overactivity after cerebral infarction. Methods: Cerebral infarction was induced by left middle cerebral artery occlusion (MCAO) in SD rats. Bladder activity was monitored with continuous infusion cystometrography in awake rats. The influences of H-89 (protein kinase A inhibitor), actinomycin D (ACD; RNA synthesis inhibitor), or NS-398 (COX-2 inhibitor) on bladder activity and gene expression (c-fos and zif268) were examined. Expressions of c-fos and zif268 mRNA in the DPT were monitored with real-time PCR. Results: In cerebral infarcted (CI) rats pretreated with vehicle, bladder capacity (BC) was significantly reduced after MCAO and remained consistently below half of pre-occlusion capacity. H-89, when administered 2 hours after MCAO, inhibited the reduction in BC. ACD also blocked reduction in BC in CI rats. In ACD-treated CI rats, BC gradually recovered … More and returned to the control level prior to MCAO within 10 hours. Treatment with NS-398 before MCAO prevented the development of bladder overactivity dose-dependently, and did not influence infarction volume. One hour after MCAO, c-fos and COX-2 mRNA expression, three hours after MCAO, zif268 mRNA expression had significantly increased as compared to those in sham operated rats. Pretreatment with MK-801, glutamatergic NMDA receptor antagonist, inhibited the development bladder overactivity and significantly reduced these gene expressions in the PTA. ACD suppressed an increase in c-fos mRNA expression 1hour after MCA occlusion as well as in zif268 3hours after MCAO. Conclusion: These results indicate that the development of bladder overactivity following MCAO is mediated by the activation of an NMDA receptor and by an RNA synthesis. Transcription in the DPT was found to be necessary for maintenance of long-lasting bladder overactivity caused by cerebral infarction. Furthermore, COX-2 molecular mechanism in the brain seems to be related to bladder overactivity. Further research on the molecular mechanisms in the brain related to bladder overactivity may lead to pharmacological therapy which targets the micturition center. Less