Orexin (OX), which regulates sleep and wakefulness and feeding behaviors has 2 isoforms, orexin-A and -B (OXA and OXB). In this study, the distribution of OXA and OXB was examined in the rat superior salivatory nucleus (SSN) using retrograde tracing and immunohistochemical and methods. OXA- and OXB-immunoreactive (-ir) nerve fibers were seen throughout the SSN. These nerve fibers surrounded SSN neurons retrogradely labeled with Fast blue (FB) from the corda-lingual nerve. FB-positive neurons had pericellular OXA- (47.5%) and OXB-ir (49.0%) nerve fibers. Immunohistochemistry for OX receptors also demonstrated the presence of OX1R and OX2R in FB-positive SSN neurons. The majority of FB-positive SSN neurons contained OX1R- (69.7%) or OX2R-immunoreactivity (57.8%). These neurons had small and medium-sized cell bodies. In addition, half of FB-positive SSN neurons which were immunoreactive for OX1R (47.0%) and OX2R (52.2%) had pericellular OXA- and OXB-ir nerve fibers, respectively. Co-expression of OX1R- and OX2R was common in FB-positive SSN neurons. The present study suggests a possibility that OXs regulate the activity of SSN neurons through OX receptors.

中文翻译：

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大鼠上唾液核中的食欲素 A 和 B

食欲素 (OX) 调节睡眠和觉醒以及进食行为，有 2 种异构体，食欲素-A 和-B（OXA 和 OXB）。在这项研究中，使用逆行示踪和免疫组织化学方法检查了 OXA 和 OXB 在大鼠上唾液核 (SSN) 中的分布。在整个 SSN 中都可以看到 OXA 和 OXB 免疫反应性 (-ir) 神经纤维。这些神经纤维围绕着 SSN 神经元，这些神经元被来自脐带舌神经的固蓝 (FB) 逆行标记。FB 阳性神经元具有细胞周 OXA- (47.5%) 和 OXB-ir (49.0%) 神经纤维。OX 受体的免疫组织化学也证明了 OX1R 和 OX2R 在 FB 阳性 SSN 神经元中的存在。大多数 FB 阳性 SSN 神经元含有 OX1R- (69.7%) 或 OX2R-免疫反应性 (57.8%)。这些神经元具有中小型细胞体。此外，对 OX1R (47.0%) 和 OX2R (52.2%) 具有免疫反应性的 FB 阳性 SSN 神经元的一半分别具有细胞周 OXA-和 OXB-ir 神经纤维。OX1R- 和 OX2R 的共表达在 FB 阳性 SSN 神经元中很常见。本研究表明 OX 可能通过 OX 受体调节 SSN 神经元的活动。