Swallowing Differences in the Male and Female Cat

Swallowing is an essential defensive maneuver that belongs to a constellation of airway protection behaviors. Human females report an increase in duration of upper esophageal sphincter (UES) opening and have differing swallow-temporal features than males. Unfortunately, there is limited research in animal models reporting sex differences of swallow metrics which are often used to study swallowing impairment. The purpose of this study was to determine if sex-related differences could be identified in the feline model regarding swallow responses. Experiments were conducted in anesthetized, tracheostomized, spontaneously breathing cats (n=32; 14 female). Electromyograms (EMG) were recorded from the diaphragm (DIA), bilateral parasternal (PSR and PSL) muscles, geniohyoid (GeHy), the bilateral transversus abdominis (ABDR and ABDL) muscles, upper esophageal sphincter (UES), thyropharyngeus (ThPh), and the thyroarytenoid adductor (ADD) muscles. The swallow response was evaluated from a protocol consisting of 3 consecutive 3-cc water trials. Females exhibited a significantly larger number of swallows than males (p = 0.038). Esophageal pressure during the Schlucketmung declined significantly during the swallow protocol in both males and females (p = 0.03). However, males had a greater negative esophageal pressure during UES opening than females (p = 0.04). There were significant timing differences between the male and female groups for thyroarytenoid adductor (p = 0.038) and Swallow TOT (p = 0.034); indicating that females have a shorter adductor activation time and faster total swallowing time. No significant differences were observed in EMG amplitudes between males and females (p > 0.05). The results of this study indicate that sex differences in swallow timing exist in this animal model, which is consistent with humans. A potential explanation for swallow differences observed may be due to changes in afferent sensitivity threshold within the pharyngeal and laryngeal area. Supported by NHLBI L30HL165496, NIH T32 HL 134621, HL 163008. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.