Weruaga Eduardo, Balkan Burcu, Koylu Ersin O, Pogun Sakire, Alonso José R
Department of Cell Biology and Pathology and Institute for Neuroscience of Castilla y León, University of Salamanca, Salamanca, Spain.
J Neurosci Res. 2002 Mar 1;67(5):689-97. doi: 10.1002/jnr.10158.
Although there is substantial evidence concerning the influence of nicotine on nitric oxide (NO) synthesis in the vascular system, there are fewer studies concerning the central nervous system. Although NO metabolites (nitrates/nitrites) increase in several rat brain regions after chronic injection of nicotine, the cellular origin of this rise in NO levels is not known. The aim of the present work was to assess the effects of repetitive nicotine administration on nitric oxide synthase (NOS) expression and activity in male and female rat brains. To determine levels of nitrate/nitrite, the Griess reaction was carried out in tissue micropunched from the frontal cortex, striatum, and accumbens of both male and female rats untreated (naïve) or injected with saline or nicotine (0.4 mg/kg for 15 days). In parallel, coronal sections of fixed brains from equally treated animals were immunostained for neuronal NOS or histochemically labelled for NADPH-diaphorase activity. Nicotine treatment increased NO metabolites significantly in all brain regions compared with naïve or saline-treated rats. By contrast, analysis of the planimetric counting of NOS/NADPH-diaphorase-positive neurons failed to demonstrate any significant effect of the nicotine treatment. A significant decrease was observed with both techniques employed in saline-injected female rats compared with naïve animals, suggesting a stress response. The mismatch between the biochemical and the histological data after chronic nicotine treatment is discussed. The up-regulation of NO sources other than neurons is proposed.
尽管有大量证据表明尼古丁对血管系统中一氧化氮（NO）合成有影响，但关于中枢神经系统的研究较少。虽然慢性注射尼古丁后，几种大鼠脑区的NO代谢产物（硝酸盐/亚硝酸盐）会增加，但这种NO水平升高的细胞来源尚不清楚。本研究的目的是评估重复给予尼古丁对雄性和雌性大鼠大脑中一氧化氮合酶（NOS）表达和活性的影响。为了测定硝酸盐/亚硝酸盐水平，对未处理（未接触过尼古丁）、注射生理盐水或尼古丁（0.4mg/kg，持续15天）的雄性和雌性大鼠的额叶皮质、纹状体和伏隔核进行组织微打孔，并进行格里斯反应。同时，对同样处理的动物的固定大脑冠状切片进行神经元NOS免疫染色或进行NADPH-黄递酶活性的组织化学标记。与未接触过尼古丁或注射生理盐水的大鼠相比，尼古丁处理显著增加了所有脑区的NO代谢产物。相比之下，对NOS/NADPH-黄递酶阳性神经元的平面计数分析未能显示尼古丁处理有任何显著影响。与未接触过尼古丁的动物相比，在注射生理盐水的雌性大鼠中，两种技术都观察到显著下降，这表明存在应激反应。讨论了慢性尼古丁处理后生化数据和组织学数据之间的不匹配。提出了除神经元外的NO来源上调的观点。
