Dellacorte C, Kalinoski D L, Huque T, Wysocki L, Restrepo D
Monell Chemical Senses Center, Philadelphia, PA 19104, USA.
Neuroscience. 1995 May;66(1):215-25. doi: 10.1016/0306-4522(94)00530-i.
Nitric oxide, a simple gas which serves as a neurotransmitter in the CNS, has been proposed to serve as an interneuronal second messenger in olfactory transduction. However, the role of nitric oxide in olfaction has been questioned by experiments in which nitric oxide synthase, the enzyme that generates nitric oxide, could not be localized to the olfactory epithelium. We have localized nitric oxide synthase to the olfactory neurons in adult rat and catfish olfactory epithelia using a modified nicotinamide adenine dinucleotide phosphate diaphorase technique. In the rat, staining was also found in cells with morphology reminiscent of microvillar olfactory cells. In contrast, the respiratory epithelium and the sustentacular cells in the olfactory epithelium displayed no staining. The nicotinamide adenine dinucleotide phosphate diaphorase reaction, which has been shown to co-localize with immunohistochemical staining for nitric oxide synthase in the brain, was stimulated by addition of the nitric oxide synthase substrate L-arginine, and was inhibited by the nitric oxide synthase inhibitor L-NG-nitro arginine, indicating that staining was specific for nitric oxide synthase. Unilateral bulbectomy, which causes degeneration of mature olfactory neurons on the bulbectomized size, markedly reduced nicotinamide adenine dinucleotide phosphate diaphorase staining. These observations were substantiated by biochemical assays for nitric oxide synthase by monitoring the production of [3H]-L-citrulline from [3H]-L-arginine. This is the first demonstration of specific NADPH diaphorase staining of mature olfactory neurons in rat and catfish olfactory epithelial suggesting the presence of nitric oxide synthase in these cells. Our histological and biochemical findings, in conjunction with data from other research, are supportive of a role for nitric oxide synthase in olfactory function.
一氧化氮是一种简单的气体，在中枢神经系统中作为神经递质，有人提出它在嗅觉转导中作为神经元间的第二信使。然而，一氧化氮在嗅觉中的作用受到了一些实验的质疑，在这些实验中，产生一氧化氮的酶——一氧化氮合酶，无法定位于嗅觉上皮。我们使用改良的烟酰胺腺嘌呤二核苷酸磷酸黄递酶技术，将一氧化氮合酶定位于成年大鼠和鲶鱼嗅觉上皮中的嗅觉神经元。在大鼠中，在形态上类似于微绒毛嗅觉细胞的细胞中也发现了染色。相比之下，嗅觉上皮中的呼吸上皮和支持细胞没有染色。烟酰胺腺嘌呤二核苷酸磷酸黄递酶反应已被证明与大脑中一氧化氮合酶的免疫组织化学染色共定位，添加一氧化氮合酶底物L-精氨酸可刺激该反应，而一氧化氮合酶抑制剂L-NG-硝基精氨酸可抑制该反应，这表明染色对一氧化氮合酶具有特异性。单侧嗅球切除会导致切除侧成熟嗅觉神经元变性，显著降低烟酰胺腺嘌呤二核苷酸磷酸黄递酶染色。通过监测[3H]-L-精氨酸生成[3H]-L-瓜氨酸来进行一氧化氮合酶的生化测定，证实了这些观察结果。这是首次在大鼠和鲶鱼嗅觉上皮中证明成熟嗅觉神经元有特异性的NADPH黄递酶染色，表明这些细胞中存在一氧化氮合酶。我们的组织学和生化研究结果，结合其他研究的数据，支持一氧化氮合酶在嗅觉功能中起作用。
