title: MSG-Evoked c-Fos Activity in the Nucleus of the Solitary Tract Is Dependent upon Fluid Delivery and Stimulation Parameters.
abstract: The marker of neuronal activation, c-Fos, can be used to visualize spatial patterns of neural activity in response to taste stimulation. Because animals will not voluntarily consume aversive tastes, these stimuli are infused directly into the oral cavity via intraoral cannulae, whereas appetitive stimuli are given in drinking bottles. Differences in these 2 methods make comparison of taste-evoked brain activity between results that utilize these methods problematic. Surprisingly, the intraoral cannulae experimental conditions that produce a similar pattern of c-Fos activity in response to taste stimulation remain unexplored. Stimulation pattern (e.g., constant/intermittent) and hydration state (e.g., water-restricted/hydrated) are the 2 primary differences between delivering tastes via bottles versus intraoral cannulae. Thus, we quantified monosodium glutamate (MSG)-evoked brain activity, as measured by c-Fos, in the nucleus of the solitary tract (nTS; primary taste nucleus) across several conditions. The number and pattern of c-Fos neurons in the nTS of animals that were water-restricted and received a constant infusion of MSG via intraoral cannula most closely mimicked animals that consumed MSG from a bottle. Therefore, in order to compare c-Fos activity between cannulae-stimulated and bottle-stimulated animals, cannulated animals should be water restricted prior to stimulation, and receive taste stimuli at a constant flow.
authors.affiliation: Rocky Mountain Taste and Smell Center, Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA and jennifer.stratford@ucdenver.edu.
authors.forename: Jennifer M
authors.identifier: http://orcid.org/0000-0001-9119-6798
authors.initials: JM
authors.lastname: Stratford
authors.affiliation: Department of Neurosurgery, University of Colorado School of Medicine, Aurora, CO 80045, USA.
authors.forename: John A
authors.identifier: http://orcid.org/0000-0003-2991-5194
authors.initials: JA
authors.lastname: Thompson
mesh_terms: D000818:Animals; D004326:Drinking; D005260:Female; D008810:Mice, Inbred C57BL; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis / Q000378:metabolism*; D012970:Sodium Glutamate / Q000008:administration & dosage / Q000378:metabolism*; D017552:Solitary Nucleus / Q000502:physiology*; D013649:Taste; D055697:Taste Perception
chemical_list: D016760:Proto-Oncogene Proteins c-fos; D012970:Sodium Glutamate
keywords: drinking bottle; intraoral cannulae; taste