Srisawat Rungrudee, Bishop Valerie R, Bull Philip M, Douglas Alison J, Russell John A, Ludwig Mike, Leng Gareth
School of Biomedical and Clinical Laboratory Sciences, College of Medicine and Veterinary Medicine, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK.
Neurosci Lett. 2004 Oct 21;369(3):191-6. doi: 10.1016/j.neulet.2004.07.045.
We examined the activation of nNOS mRNA expression within the supraoptic and paraventricular nuclei (SON and PVN) of the hypothalamus. In salt-loaded rats nNOS mRNA expression was significantly increased in both nuclei. In rats given i.p. injections of 1.5 M NaCl (4 ml/kg), a small but significant increase in nNOS mRNA expression in the SON and PVN was found 6 h after injection; no change was detected 2 or 4 h after injection. In rats in which hyponatraemia had been induced experimentally, nNOS mRNA was downregulated in the SON, and expression levels were not increased within 4 h after intense acute osmotic stimuli. Finally, neurons of the SON were antidromically-activated by neural stalk stimulation for 2 h. No increase of nNOS mRNA expression in the SON was observed 2 h after stimulation. Thus, increased electrical activity is not directly coupled to rapidly increased expression of nNOS mRNA, and hence acute increases in nNOS mRNA expression are unlikely to play a role in short-term adaptation of the magnocellular system to osmotic stimulation.
我们研究了下丘脑视上核和室旁核（SON和PVN）内nNOS mRNA表达的激活情况。在盐负荷大鼠中，两个核内的nNOS mRNA表达均显著增加。给大鼠腹腔注射1.5 M NaCl（4 ml/kg）后，注射后6小时SON和PVN中nNOS mRNA表达有小幅度但显著的增加；注射后2或4小时未检测到变化。在实验性诱导低钠血症的大鼠中，SON中nNOS mRNA下调，在强烈急性渗透刺激后4小时内表达水平未增加。最后，通过刺激神经柄对SON的神经元进行2小时的逆向激活。刺激后2小时未观察到SON中nNOS mRNA表达增加。因此，电活动增加与nNOS mRNA表达的快速增加没有直接关联，因此nNOS mRNA表达的急性增加不太可能在大细胞系统对渗透刺激的短期适应中起作用。
