Ege University School of Medicine Department of Physiology, Izmir, Turkey.
Brain Res. 2011 Jan 12;1368:134-42. doi: 10.1016/j.brainres.2010.10.090. Epub 2010 Nov 2.
NO (nitric oxide) produced in limbic brain regions has important roles in the regulation of autonomic nervous system and HPA axis activity, anxiety, fear learning, long-term memory formation, and depression. NO is synthesized from l-arginine in a reaction catalyzed by nitric oxide synthase (NOS). Neuronal nitric oxide synthase (nNOS), one of the three isoforms of NOS, is synthesized constitutively in nerve cells. Increasing evidence indicates that nNOS expression in the nervous system may be regulated by stress and nicotinic receptors. Furthermore, data obtained from several studies suggest that signaling pathways induced by stress and nicotinic receptors may converge on various signal transduction molecules to regulate nNOS expression in brain. In the present study, we used Western Blot analysis to test the effect of forced swim stress, chronic nicotine administration, and the combined effect of both procedures on nNOS expression in the hippocampus, amygdala and frontal cortex of the male and female rat brain. Basal nNOS levels of the three brain regions examined did not show sex differences. However, forced swim stress and chronic nicotine administration increased nNOS expression in the hippocampus of female rats. When stress and nicotine were applied together, no additional increment was observed. Stress and nicotine did not regulate nNOS expression in the amygdala and the frontal cortex of either sex. Data obtained from the present study indicate that the regulation of stress and nicotine induced-nNOS expression in rat hippocampus shows sexual dimorphism and nNOS expression in the female rat hippocampus increases by nicotine and stress.
脑中产生的一氧化氮（NO）在自主神经系统和 HPA 轴活动、焦虑、恐惧学习、长期记忆形成和抑郁的调节中具有重要作用。NO 是由精氨酸在一氧化氮合酶（NOS）催化的反应中合成的。神经元型一氧化氮合酶（nNOS）是 NOS 的三种同工酶之一，在神经细胞中持续合成。越来越多的证据表明，神经系统中的 nNOS 表达可能受到应激和烟碱受体的调节。此外，多项研究的数据表明，应激和烟碱受体诱导的信号通路可能集中在各种信号转导分子上，以调节大脑中的 nNOS 表达。在本研究中，我们使用 Western Blot 分析来测试强迫游泳应激、慢性尼古丁给药以及这两种程序的组合对雄性和雌性大鼠大脑海马体、杏仁核和额叶皮质中 nNOS 表达的影响。所检查的三个脑区的基础 nNOS 水平没有显示出性别差异。然而，强迫游泳应激和慢性尼古丁给药增加了雌性大鼠海马体中的 nNOS 表达。当应激和尼古丁一起应用时，没有观察到额外的增加。应激和尼古丁没有调节两性的杏仁核和额叶皮质中的 nNOS 表达。本研究获得的数据表明，应激和尼古丁诱导的 nNOS 表达在大鼠海马体中的调节存在性别二态性，并且尼古丁和应激增加了雌性大鼠海马体中的 nNOS 表达。
