Chorda tympani responses in two inbred strains of mice with different taste preferences

Behavioral studies suggest that there are significant differences in the taste systems of the inbred mouse (Mus musculus) strains: C57BL/6J (B6) and DBA/2J (D2). In an attempt to understand the biological basis of the behavioral differences, we recorded whole-nerve chorda tympani responses to taste solutions and compared the results to intake of similar solutions in nondeprived mice. Stimuli included a test series composed of 0.1 M sodium chloride, 0.3 M sucrose, 10 mM sodium saccharin, 3 mM hydrochloric acid, and 3 mM quinine hydrochloride, as well as concentration series for the same substances. Neural activity of the chorda tympani that was evoked by sucrose, saccharin, or NaCl was greater in B6 than D2 mice; and neural threshold for sucrose was lower in B6 mice, but neural thresholds for HCl and quinine were lower in D2 mice. B6 mice drank more sucrose and saccharin but less quinine than D2 mice; thus, sucrose and saccharin preference were positively correlated, but NaCl and quinine aversiveness were negatively correlated with the chorda tympani results. Nonetheless, genes involved in the structuring of taste receptors and/or the chordae tympani, which transduce taste stimuli having diverse perceptual qualities, differ for the two mouse strains.