Supportive effect of interferential current stimulation on susceptibility of swallowing in guinea pigs

• Published in: Experimental brain research Vol. 236; no. 10; pp. 2661 - 2676
• Main Authors: Umezaki, Toshiro, Sugiyama, Yoichiro, Fuse, Shinya, Mukudai, Shigeyuki, Hirano, Shigeru
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.10.2018; Springer; Springer Nature B.V
• Subjects: Action Potentials - drug effects; Action Potentials - physiology; Afferent Pathways - physiology; Animals; Biomedical and Life Sciences; Biomedicine; Biophysics; Blood pressure; Brain stimulation; Deglutition; Deglutition - physiology; Electric Stimulation; Electromyography; Excitatory Amino Acid Agonists - toxicity; Guinea Pigs; Kainic acid; Kainic Acid - toxicity; Laryngeal Nerves - physiology; Larynx; Motor task performance; Neck; Neurology; Neurons; Neurons - drug effects; Neurons - physiology; Neurosciences; Pharynx; Pharynx - physiology; Physiological aspects; Reaction Time - physiology; Reflex - physiology; Research Article; Sensory neurons; Solitary Nucleus - cytology; Solitary Nucleus - injuries; Solitary Nucleus - physiology; Solitary tract nucleus; Swallowing; Interferential current stimulation; Nucleus tractus solitarius; Swallowing; Guinea pigs
• ISSN: 0014-4819; 1432-1106
• DOI: 10.1007/s00221-018-5325-0

Sensory-motor control of the pharyngeal swallow requires sensory afferent inputs from the pharynx and larynx evoked by introducing bolus into the pharynx. Patients with reduced sensitivity of the pharynx and larynx are likely to have a swallowing impairment, such as pre-swallow aspiration due to delayed swallow triggering. Interferential current stimulation applied to the neck is thought to improve the swallowing function of dysphagic patients, although the mechanism underlying the facilitatory effect of such stimulation remains unknown. In the present study, we examined the changes in the elicitability of swallowing due to the stimulation and the responses of the swallowing-related neurons in the nucleus tractus solitarius and in the area adjacent to the stimulation in decerebrate and paralyzed guinea pigs. The swallowing delay time was shortened by the stimulation, whereas the facilitatory effect of eliciting swallowing was attenuated by kainic acid injection into the nucleus tractus solitarius. Approximately half of the swallowing-related neurons responded to the stimulation. These data suggest that the interferential current stimulation applied to the neck could enhance the sensory afferent pathway of the pharynx and larynx, subserving excitatory inputs to the neurons of the swallowing pattern generator, thereby facilitating the swallowing reflex.