title: Intragastric gavage with denatonium benzoate acutely induces neuronal activation in the solitary tract nucleus via the vagal afferent pathway.
abstract: Natural toxic substances have a bitter taste and their ingestion sends signals to the brain leading to aversive oral sensations. In the present study, we investigated chronological changes in c-Fos immunoreactivity in the nucleus tractus solitarius (NTS) to study the bitter taste reaction time of neurons in the NTS. Equal volumes (0.5 mL) of denatonium benzoate (DB), a bitter tastant, or its vehicle (distilled water) were administered to rats intragastrically. The rats were sacrificed at 0, 0.5, 1, 2, 4, 8, or 16 h after treatment. In the vehicle-treated group, the number of c-Fos-positive nuclei started to increase 0.5 h after treatment and peaked 2 h after gavage. In contrast, the number of c-Fos-positive nuclei in the DB-treated group significantly increased 1 h after gavage. Thereafter, the number of c-Fos immunoreactive nuclei decreased over time. The number of c-Fos immunoreactive nuclei in the NTS was also increased in a dose-dependent manner 1 h after gavage. Subdiaphragmatic vagotomy significantly decreased DB-induced neuronal activation in the NTS. These results suggest that intragastric DB increases neuronal c-Fos expression in the NTS 1 h after gavage and this effect is mediated by vagal afferent fibers.
authors: Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Korea.
authors: Hyo Young
authors: HY
authors: Jung
authors: Woosuk
authors: W
authors: Kim
authors: Dae Young
authors: DY
authors: Yoo
authors: Sung Min
authors: SM
authors: Nam
authors: Jong Whi
authors: JW
authors: Kim
authors: Jung Hoon
authors: JH
authors: Choi
authors: Yeo Sung
authors: YS
authors: Yoon
authors: Hye Young
authors: HY
authors: Kim
authors: In Koo
authors: IK
authors: Hwang
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D007267:Injections / Q000662:veterinary; D008024:Ligands; D008297:Male; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D017552:Solitary Nucleus / Q000502:physiology*; D014630:Vagus Nerve / Q000187:drug effects* / Q000502:physiology*; D000098706:Taste Receptors, Type 2
chemical_list: D000276:Adjuvants, Immunologic; D008024:Ligands; D016760:Proto-Oncogene Proteins c-fos; D000644:Quaternary Ammonium Compounds; D043562:Receptors, G-Protein-Coupled; D000098706:Taste Receptors, Type 2; C043414:denatonium
keywords: bitter tastant; c-Fos; nucleus tractus solitarius; vagal afferent fibers; vagotomy