Variability of the Pharyngeal Phase of Swallow in the Cat

Abstract

ObjectiveThe pharyngeal phase of swallow has been thought to be a stereotypical motor behavior.Study DesignThis is a prospective, preclinical, hypothesis driven, one group by three-task design.MethodsWe sought to compare the effects of pharyngeal swabbing, water only, and water plus punctate mechanical stimulation on the spatiotemporal features of the pharyngeal phase of swallow in the cat. Swallow was elicited under these three conditions in six anaesthetized cats. Electromyographic activity was recorded from seven muscles used to evaluate swallow: mylohyoid, geniohyoid, thyrohyoid, thyroarytenoid, thyropharyngeus, cricopharyngeus, and parasternal.ResultsPharyngeal swabbing in comparison to the other stimulus conditions, results in decreases in post-swallow cricopharyngeus activity (upper esophageal sphincter); a significant increase in parasternal (schluckatmung; swallow breath) activity; and increases in thyrohyoid (laryngeal elevator), thyroarytenoid (laryngeal adductor) and parasternal muscles burst duration. Pearson correlations were found of moderate strength between 19% of burst duration comparisons and weak to moderate relationships between 29% of burst amplitude comparisons. However, there were no positive significant relationships between phase durations and electromyogram amplitudes between any of the muscles studied during swallow.ConclusionsThe results support the concept that a stereotypical behavior, such as pharyngeal swallowing in animal models, can be modified by sensory feedback from pharyngeal mucosal mechanoreceptors. Furthermore, differences in swallow phase durations and amplitudes provide evidence that separate regulatory mechanisms exist which regulate spatial and temporal aspects of the behavior.

Sex-specific vagal and spinal modulation of swallow and its coordination with breathing

“…The results of this study further support our hypothesis that there are different central mechanisms for regulating swallow amplitude and duration. Clinically, it has been assumed that swallow duration positively correlates with force production, as defined by swallow phase relationships in videofluoroscopy exams [13]. We have now established that swallow-related EMG amplitude and duration are not correlated in cats [13,46,73], humans [74,75], or rats (present study).…”

“…These pivotal studies form a foundation for the swallow field, and since then swallow has been studied in vivo in the mouse [9], rat [10,11], bat [12], cat [13][14][15][16][17][18][19], rabbit [20,21], pig [22], sheep [23], goat [24], monkey [25,26], and human [27][28][29][30][31]. Swallow has also been studied in situ [19,[32][33][34] and in vitro [35] and modeled in silico [36,37].…”

Involvement of the epithelial sodium channel in initiation of mechanically evoked swallows in anaesthetized rats

“…Additionally, Spearman et al . () reported that spatiotemporal control of swallowing‐related muscle activity was modified by sensory feedback from mechanoreceptors in anaesthetized cats. Although swallowing‐related muscle activity was not changed by benzamil application, we should consider the possibility of modulation of swallowing motor activity by amiloride analogues.…”

“…Jafari et al (2003) suggested that the afferent signals from the internal branch of the SLN, which contains afferents from the supraglottic larynx and epiglottis, play an important role in normal swallowing, particularly in facilitating laryngeal closure during swallowing. Additionally, Spearman et al (2014) reported that spatiotemporal control of swallowing-related muscle activity was modified by sensory feedback from mechanoreceptors in anaesthetized cats. Although swallowing-related muscle activity was not changed by benzamil application, we should consider the possibility of modulation of swallowing motor activity by amiloride analogues.…”

Neurons in the dorsomedial medulla contribute to swallow pattern generation: Evidence of inspiratory activity during swallow

“…Eight muscles were used to evaluate swallow occurrence: mylohyoid, geniohyoid, thyrohyoid, thyropharyngeus, thyroarytenoid, cricopharyngeus, parasternal, and costal diaphragm. These muscles span the actions during the pharyngeal phase of swallow: a) mylohyoid, geniohyoid and thyrohyoid for hyolaryngeal elevation; b) thyropharyngeus for inferior pharyngeal constrictor; c) cricopharyngeus for upper esophageal sphincter regulation; d) thyroarytenoid for laryngeal adduction; and e) parasternal and costal diaphragm for inspiratory activity [ 12 , 13 , 15 , 24 ].…”