Department of Neurological Surgery and Kentucky Spinal Cord Injury Research Center, College of Medicine, University of Louisville, Louisville, Kentucky, United States of America.
Department of Physiology, University of Louisville, Louisville, Kentucky, United States of America.
PLoS One. 2021 Apr 2;16(4):e0248994. doi: 10.1371/journal.pone.0248994. eCollection 2021.
Swallow is a complex behavior that consists of three coordinated phases: oral, pharyngeal, and esophageal. Esophageal distension (EDist) has been shown to elicit pharyngeal swallow, but the physiologic characteristics of EDist-induced pharyngeal swallow have not been specifically described. We examined the effect of rapid EDist on oropharyngeal swallow, with and without an oral water stimulus, in spontaneously breathing, sodium pentobarbital anesthetized cats (n = 5). Electromyograms (EMGs) of activity of 8 muscles were used to evaluate swallow: mylohyoid (MyHy), geniohyoid (GeHy), thyrohyoid (ThHy), thyropharyngeus (ThPh), thyroarytenoid (ThAr), cricopharyngeus (upper esophageal sphincter: UES), parasternal (PS), and costal diaphragm (Dia). Swallow was defined as quiescence of the UES with overlapping upper airway activity, and it was analyzed across three stimulus conditions: 1) oropharyngeal water infusion only, 2) rapid esophageal distension (EDist) only, and 3) combined stimuli. Results show a significant effect of stimulus condition on swallow EMG amplitude of the mylohyoid, geniohyoid, thyroarytenoid, diaphragm, and UES muscles. Collectively, we found that, compared to rapid cervical esophageal distension alone, the stimulus condition of rapid distension combined with water infusion is correlated with increased laryngeal adductor and diaphragm swallow-related EMG activity (schluckatmung), and post-swallow UES recruitment. We hypothesize that these effects of upper esophageal distension activate the brainstem swallow network, and function to protect the airway through initiation and/or modulation of a pharyngeal swallow response.
吞咽是一种复杂的行为，由三个协调的阶段组成：口腔、咽和食管。已经证明食管扩张（EDist）可以引起咽吞咽，但 EDist 诱导的咽吞咽的生理特征尚未被具体描述。我们检查了快速 EDist 在有和没有口腔水刺激的情况下对口腔吞咽的影响，在自主呼吸、戊巴比妥钠麻醉的猫中（n = 5）。使用 8 块肌肉的肌电图（EMG）来评估吞咽：颏舌肌（MyHy）、颏舌骨肌（GeHy）、舌骨肌（ThHy）、甲状舌骨肌（ThPh）、甲状软骨肌（ThAr）、环咽肌（UES）、胸骨旁肌（PS）和肋间膈肌（Dia）。吞咽被定义为 UES 静止，同时伴有重叠的上气道活动，它在三种刺激条件下进行分析：1）仅口腔水输注，2）快速食管扩张（EDist），3）联合刺激。结果表明，刺激条件对颏舌肌、颏舌骨肌、甲状软骨肌、膈肌和 UES 肌肉的吞咽 EMG 幅度有显著影响。总的来说，我们发现，与单独快速颈部食管扩张相比，快速扩张结合水灌注的刺激条件与增加的喉内收肌和膈肌吞咽相关 EMG 活动（吞咽）以及吞咽后 UES 募集有关。我们假设，这些食管上部扩张的影响激活了延髓吞咽网络，并通过启动和/或调节咽吞咽反应来起到保护气道的作用。
