Differential effects of a 5‐HT1A receptor agonist on breathing and swallow motor patterns

Abstract

Swallow disorder (dysphagia) can cause aspiration and lead to pneumonia in a number of patient populations, including individuals with cervical spinal cord injury. Dysphagia is characterized by dysfunction in the swallow motor pattern, which is a sequential activation of muscles that propels the bolus into the esophagus and prevents entry into the airway. Diaphragm activity contributes to effective swallow by generating negative pressure which draws the bolus into the esophagus. There currently are no effective pharmacological treatments for dysphagia, and we aim to explore the effects of a potential treatment agent by first assessing its effects on baseline breathing and swallow. We use EMG to record breathing patterns and water‐induced swallow in pentobarbital‐anesthetized spontaneously breathing cats. EMGs are recorded from the mylohyoid, thyrohyoid, thyroarytenoid, thyropharyngeus, cricopharyngeus (upper esophageal sphincter), and diaphragm muscles, and trans‐diaphragmatic pressure is measured by monitoring esophageal and stomach pressures. The serotonin 5‐HT1A receptor agonist 8‐OH‐DPAT is delivered via the vertebral artery in doses ranging from 1μg/kg – 50 μg/kg. We report here differential effects of low‐dose (3 μg/kg) and high dose (30 μg/kg) 8‐OH‐DPAT on swallow‐breathing coordination, behavior‐specific muscle recruitment patterns, and the sequential muscle activation necessary for proper movement of a bolus through the pharynx. This work will potentially inform treatment of patients with dysphagia, including those with cervical spinal cord injuries.Support or Funding InformationThis work was supported by NIH grants HL 111215, HL 103415 and OT20D001983, the Craig F. Neilson Foundation Pilot Research Grant 546714, Veterans Affairs Rehabilitation, Research and Development RCSB92495 (DRH), Kentucky Spinal Cord and Head Injury Research Trust, Rebecca F. Hammond Endowment (DRH), and the Commonwealth of Kentucky Challenge for Excellence.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.