title: Central inhibition of initiation of swallowing by systemic administration of diazepam and baclofen in anaesthetized rats.
abstract: Dysphagia is caused not only by neurological and/or structural damage but also by medication. We hypothesized memantine, dextromethorphan, diazepam, and baclofen, all commonly used drugs with central sites of action, may regulate swallowing function. Swallows were evoked by upper airway (UA)/pharyngeal distension, punctate mechanical stimulation using a von Frey filament, capsaicin or distilled water (DW) applied topically to the vocal folds, and electrical stimulation of a superior laryngeal nerve (SLN) in anesthetized rats and were documented by recording electromyographic activation of the suprahyoid and thyrohyoid muscles and by visualizing laryngeal elevation. The effects of intraperitoneal or topical administration of each drug on swallowing function were studied. Systemic administration of diazepam and baclofen, but not memantine or dextromethorphan, inhibited swallowing evoked by mechanical, chemical, and electrical stimulation. Both benzodiazepines and GABAAreceptor antagonists diminished the inhibitory effects of diazepam, whereas a GABABreceptor antagonist diminished the effects of baclofen. Topically applied diazepam or baclofen had no effect on swallowing. These data indicate that diazepam and baclofen act centrally to inhibit swallowing in anesthetized rats.NEW & NOTEWORTHYSystemic administration of diazepam and baclofen, but not memantine or dextromethorphan, inhibited swallowing evoked by mechanical, chemical, and electrical stimulation. Both benzodiazepines and GABAAreceptor antagonists diminished the inhibitory effects of diazepam, whereas a GABABreceptor antagonist diminished the effects of baclofen. Topical applied diazepam or baclofen was without effect on swallowing. Diazepam and baclofen act centrally to inhibit swallowing in anesthetized rats.
authors.affiliation: Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan; and tsujimura@dent.niigata-u.ac.jp.
authors.forename: Takanori
authors.initials: T
authors.lastname: Tsujimura
authors.affiliation: Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan; and.
authors.forename: Shogo
authors.initials: S
authors.lastname: Sakai
authors.affiliation: Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan; and.
authors.forename: Taku
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan; and.
authors.forename: Izumi
authors.initials: I
authors.lastname: Ujihara
authors.affiliation: Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan; and.
authors.forename: Kojun
authors.initials: K
authors.lastname: Tsuji
authors.affiliation: Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan; and.
authors.forename: Jin
authors.initials: J
authors.lastname: Magara
authors.affiliation: Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland.
authors.forename: Brendan J
authors.initials: BJ
authors.lastname: Canning
authors.affiliation: Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan; and.
authors.forename: Makoto
authors.initials: M
authors.lastname: Inoue
mesh_terms: D000818:Animals; D001418:Baclofen / Q000008:administration & dosage*; D001921:Brain / Q000187:drug effects / Q000502:physiology*; D003679:Deglutition / Q000187:drug effects* / Q000502:physiology*; D003975:Diazepam / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D008297:Male; D009125:Muscle Relaxants, Central / Q000008:administration & dosage; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D009125:Muscle Relaxants, Central; D001418:Baclofen; D003975:Diazepam
keywords: GABA receptor; NMDA receptor; dysphagia; superior laryngeal nerve; swallowing reflex