Preferences of 14 rat strains for 17 taste compounds

Abstract

TORDOFF, M.G., L.K. ALARCON AND M.P. LAWLER. Preferences of 14 rat strains for 17 taste compounds. PHYSIOL BEHAV 00(0) 000-000, 2008.--Two-bottle choice tests were used to assess the taste preferences of 8 male and 8 female rats from 3 outbred strains (SD, LE, WI) and 11 inbred strains (BN, BUF, COP, DA, Dahl-S, F344, FHH, LEW, Noble, PVG, SHR). Each rat received a series of 109 48-h tests with a choice between water and a "taste solution". Four to eight concentrations of the following compounds were tested: NaCl, CaCl 2 , NH 4 Cl, KCl, MgCl 2 , saccharin, sucrose, ethanol, HCl, citric acid, quinine hydrochloride (QHCl), caffeine, denatonium, monosodium glutamate (MSG), Polycose, corn oil, and capsaicin. Strain differences (p<0.001) were observed in preferences for at least one concentration of all compounds tested except denatonium (p = 0.0015). There were also strain differences in the following ancillary measures: fungiform papillae number, water intake, food intake, and body weight. There were sex differences in food intake and body weight but no concerted sex differences in any of the other measures, including preferences for any taste solution. This comprehensive source of information can be used to guide the choice of appropriate rat strains and taste solution concentrations for future genetic studies. Keywordssweet; sour; salty; bitter; umami; calcium; oil; trigeminal; strain survey Rats have been used in many experiments to understand the mechanisms underlying the selection of nutrients and taste compounds. The large majority of these studies have been focused on physiological and behavioral controls of ingestion but rarely on genetic ones. The genetic approach has been spearheaded by work in mice, and has led to several recent important advances, such as the identification of sweet, sour, bitter and umami receptors [reviews (4,10,76)]. One reason for this is that genetic and molecular tools are available for the mouse but not well-developed for the rat, although this is changing [e.g., (2,54,55,62,74)]. Another is that there are few appropriate taste phenotype data available for the rat. Genetic analyses in mice generally begin with the discovery of phenotypic differences among inbred strains but most studies aimed at understanding rat taste preferences have used outbred strains. There are a few comparisons of different rat strain preferences for sodium and ethanol (see below) but very limited data involving other taste compounds.The purpose of this study was to provide comprehensive information about the taste preferences of rats that could be used as the basis for subsequent genetic analyses. To this end, we used Address for all correspondence: Michael G. Tordoff, Monell Chemical Senses Center, 3500 Market St, Philadelphia, PA 19104, Phone: (267)-519-4805, Fax: (267)-519-4738, e-mail: tordoff@monell.org. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscri...

Opioids in the Hypothalamic Paraventricular Nucleus Stimulate Ethanol Intake

“…Taste reactivity tests demonstrate that rats consider ethanol to contain both sweet and bitter components (Kiefer, 1995). Additionally, in taste preference tests, Sprague-Dawley rats show a preference for ethanol compared to water when it is in concentrations of 1-2% but exhibit a robust avoidance of concentrations above 6% (Morrow et al, 1993; Tordoff et al, 2008). The DAMGO results in the present study are consistent with the view that the μ-receptor system in the PVN may stimulate consummatory behavior as a function of taste (Giraudo et al, 1999; Kelley et al, 2002; Woolley et al, 2007).…”

ß-Catenin signaling regulates temporally discrete phases of anterior taste bud development

“…Because taste bud precursor patterning, although initiated by β-catenin function, is subsequently regulated by a host of signals acting on a broadly competent epithelium, small changes in their relative signal strengths would be expected to alter taste bud pattern. In fact, in rodents and humans, the number of fungiform taste buds and papillae is highly variable (Bartoshuk et al, 1996;Fischer et al, 2013;Miller, 1988;Miller and Reedy, 1990), and this variability might be functionally important, as taste papilla number may be correlated with differences in taste responses and ultimately influence taste behavior and diet (Bartoshuk et al, 1996;Tordoff et al, 2008).…”

Chorda tympani nerve modulates the rat's avoidance of calcium chloride

“…First, calcium-liking appears most prominent in young, growing rats, whereas the rats used here were adults that had largely plateaued in growth. Second, and more critically, calcium-liking is rat strain-specific and it does not include the Wistar strain used here [2]. Thus, a preference for calcium relative to water would not be expected in the subjects of this experiment.…”

“…It is therefore not surprising that calcium intake is also controlled, and that calcium-replete rats and mice generally avoid calcium solutions at the concentrations that are typically used in psychophysical experiments (i.e., 10 – 300 mM) [1,2]. Restraints on calcium intake prevent large volumes of concentrated calcium from overwhelming homeostatic controls.…”