Endo Daisuke, Yamamoto Yoshio, Yamaguchi-Yamada Misuzu, Nakamuta Nobuaki, Taniguchi Kazuyuki
Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan.
J Vet Med Sci. 2011 Apr;73(4):423-30. doi: 10.1292/jvms.10-0353. Epub 2010 Nov 5.
Nitric oxide (NO) is a free radical and produced from L-arginine by nitric oxide synthase (NOS). Since NO is recently suggested to be involved in olfactory perception, the expression of eNOS, an isoform of NOS, was examined in the rat olfactory epithelium. The activity of NADPH-diaphorase was also examined as a marker of NOS. In the dorsomedial region of the nasal cavity, intensely positive reactions for NADPH-diaphorase were observed in the entire cytoplasm of sensory cells (olfactory cells). By immunohistochemistry, intensely positive reactions for eNOS were also found in the dorsomedial region of the nasal cavity. These reactions were observed on the free border of the olfactory epithelium. By immunoelectron microscopy, positive reactions for eNOS were found in the cilia of olfactory cells. In addition, in situ hybridization analysis of the olfactory epithelium revealed the expression of eNOS mRNA in the olfactory cells. These results indicate the presence of eNOS in the olfactory cells of the rat, and differential expression of eNOS in the olfactory epithelium depending on the regions of the nasal cavity. In addition, NO produced by eNOS may be involved in olfactory perception in the cilia of olfactory cells.
一氧化氮（NO）是一种自由基，由一氧化氮合酶（NOS）催化L-精氨酸生成。由于最近有研究表明NO参与嗅觉感知，因此我们检测了大鼠嗅觉上皮中NOS的一种同工酶——内皮型一氧化氮合酶（eNOS）的表达。同时，我们还检测了NADPH-黄递酶的活性作为NOS的标志物。在鼻腔的背内侧区域，感觉细胞（嗅觉细胞）的整个细胞质中均观察到强烈的NADPH-黄递酶阳性反应。通过免疫组织化学方法，在鼻腔的背内侧区域也发现了强烈的eNOS阳性反应。这些反应出现在嗅觉上皮的游离边界处。通过免疫电子显微镜观察，在嗅觉细胞的纤毛中发现了eNOS阳性反应。此外，对嗅觉上皮进行原位杂交分析显示，嗅觉细胞中存在eNOS mRNA的表达。这些结果表明，大鼠嗅觉细胞中存在eNOS，并且在嗅觉上皮中，eNOS的表达因鼻腔区域不同而存在差异。此外，由eNOS产生的NO可能参与了嗅觉细胞纤毛的嗅觉感知过程。
