Das Rajat K, Herr Kate B, Parkar Anjum, Kubin Leszek
Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
Respir Physiol Neurobiol. 2019 Feb;260:105-113. doi: 10.1016/j.resp.2018.11.005. Epub 2018 Nov 15.
Hypoglossal (XII) motoneurons are activated by type 2 receptors for serotonin (5-HT). This activation is especially strong during wakefulness which facilitates diverse motor functions of the tongue, including the maintenance of upper airway patency in obstructive sleep apnea (OSA) patients. We tested whether 5-HT receptor levels in the XII nucleus vary with intensity of tongue use. Three groups of rats were housed overnight under conditions of increasing oromotor activity: W-water available ad lib; S-sweetened water to stimulate drinking; S + O-sweetened water + oil applied on fur to increase grooming. After the exposures, immunostaining for 5-HT, but not 5-HT, receptors was higher in the XII nucleus in S + O than in W rats (65 ± 1.8 (SE) vs. 60 ± 2.0 arbitrary units; p = 0.008). In the medullary raphé obscurus region, the percentage of c-Fos-positive 5-HT cells was 13% higher (p = 0.03) in S + O than in W rats. The positive feedback between tongue use and 5-HT receptor immunostaining reveals a novel mechanism potentially relevant for OSA and neuromuscular disorders.
舌下神经（XII）运动神经元由5-羟色胺（5-HT）的2型受体激活。这种激活在清醒期间尤为强烈，有助于舌头的多种运动功能，包括维持阻塞性睡眠呼吸暂停（OSA）患者的上呼吸道通畅。我们测试了舌下神经核中5-HT受体水平是否随舌头使用强度而变化。将三组大鼠在增加口面部运动活动的条件下饲养过夜：W组——随意提供水；S组——用糖水刺激饮水；S+O组——用糖水并在皮毛上涂抹油以增加梳理行为。暴露后，S+O组大鼠舌下神经核中5-HT₂受体的免疫染色高于W组大鼠（65±1.8（标准误）对60±2.0任意单位；p=0.008），而5-HT₁受体的免疫染色则无差异。在延髓中缝隐核区域，S+O组大鼠中c-Fos阳性5-HT细胞的百分比比W组大鼠高13%（p=0.03）。舌头使用与5-HT₂受体免疫染色之间的正反馈揭示了一种可能与OSA和神经肌肉疾病相关的新机制。
