title: Vagal afferent activation induces salivation and swallowing-like events in anesthetized rats.
abstract: The aim of this study was to clarify the effect of vagal afferent activation on salivation and swallowing-like events. Salivation is part of a reflex induced by stimulation of the oral area during feeding or chewing. Recently, we reported that nausea induced by gastroesophageal reflux (GER) activation produced salivation and swallowing in humans. Here, we investigated the ability of visceral sensation to enhance salivation and swallowing in rodents in order to inform the mechanism of GER-mediated stomatognathic activation. First, we administered LiCl to anesthetized male rats to induce nausea. LiCl significantly increased salivation and increased the activity of the vagal afferent nerve. Next, we simultaneously recorded salivation and swallowing using an electrode attached to the mylohyoid muscle during vagal afferent stimulation in a physiological range of frequencies. Vagal afferent stimulation significantly increased salivation and swallowing-like events in a frequency-dependent manner. A muscle relaxant, vecuronium bromide, diminished the swallowing-like response but did not affect salivation. These results indicate that visceral sensation induces salivation and swallowing-like events in anesthetized rodents through vagal afferent activation.
authors.affiliation: Department of Orthodontics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan; and.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Ueda
authors.affiliation: Department of Orthodontics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan; and.
authors.forename: Mayu
authors.initials: M
authors.lastname: Suga
authors.affiliation: Department of Orthodontics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan; and.
authors.forename: Takakazu
authors.initials: T
authors.lastname: Yagi
authors.affiliation: Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
authors.forename: Ikue
authors.initials: I
authors.lastname: Kusumoto-Yoshida
authors.affiliation: Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Kashiwadani
authors.affiliation: Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kuwaki
authors.affiliation: Department of Orthodontics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan; and miyawaki@dent.kagoshima-u.ac.jp.
authors.forename: Shouichi
authors.initials: S
authors.lastname: Miyawaki
mesh_terms: D000344:Afferent Pathways / Q000502:physiology*; D000758:Anesthesia; D000818:Animals; D003679:Deglutition / Q000502:physiology*; D004558:Electric Stimulation; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012018:Reflex / Q000502:physiology*; D012472:Salivation / Q000502:physiology*; D014630:Vagus Nerve / Q000502:physiology*
keywords: salivation; swallowing; vagal nerve