Beta-galactosidase staining in the nucleus of the solitary tract of Fos-Tau-LacZ mice is unaffected by monosodium glutamate taste stimulation.
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ABSTRACT: Fos-Tau-LacZ (FTL) transgenic mice are used to visualize the anatomical connectivity of neurons that express c-Fos, an immediate early gene, in response to activation. In contrast to typical c-Fos protein expression, which is localized to the nucleus of stimulated neurons, activation of the c-Fos gene results in beta galactosidase (?-gal) expression throughout the entire cytoplasm of activated cells in FTL mice; thereby making it possible to discern the morphology of c-Fos expressing cells. This can be an especially important tool in brain areas in which function may be related to cell morphology, such as the primary taste/viscerosensory brainstem nucleus of the solitary tract (nTS). Thus, to further characterize FTL activity in the brain, the current study quantified both ?-gal enzymatic activity as well as c-Fos protein expression in the nTS under a variety of experimental conditions (no stimulation, no stimulation with prior overnight food and water restriction, monosodium glutamate taste stimulation, and monosodium glutamate taste stimulation with perfusion 5 h post stimulation). Contrary to previous research, we found that ?-gal activity (both labeled cell bodies and overall number of labeled pixels) was unchanged across all experimental conditions. However, traditional c-Fos protein activity (both cell bodies and number of activated pixels) varied significantly across experimental conditions, with the greatest amount of c-Fos protein label found in the group that received monosodium glutamate taste stimulation. Interestingly, although many c-Fos positive cells were also ?-gal positive in the taste stimulated group, some c-Fos protein labeled cells were not co-labeled with ?-gal. Together, these data suggest that ?-gal staining within the nTS reflects a stable population of ?-gal- positive neurons whose pattern of expression is unaffected by experimental condition.
SUBMITTER: Stratford JM
PROVIDER: S-EPMC4156431 | biostudies-literature | 2014
REPOSITORIES: biostudies-literature
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