Measuring gustatory variation in mice: a short-term fluid-intake test.

A short-term fluid-intake test is described which is directed at the study of individual variation in gustation in laboratory mice. To avoid position preferences associated with two-bottle tests, single graduated cylinders are used to present the solution. Intake of water and solutions is recorded for a 6-h period beginning 3 h prior to the dark phase of the light cycle. The timing of data collection ensures a stable baseline of fluid intake because it coincides with the period in which mice begin to drink. Food and water are available ad lib. at all other times so the test avoids the water restriction that is often used in gustatory studies. We report normative data on ten commonly used inbred strains for sucrose (100 mM), saccharin (10 mM), quinine (1.1 mM), HCI (1 and 3 mM). NaCl (320 mM), and monosodium glutamate (150 mM). Strain differences were pronounced for all tastants. Concurrent measures of food and fluid intake by C57BL/6J and DBA/2J mice demonstrated that the short-term reduction of fluid intake resulting from 6-h quinine administration, which was restricted to C57BL/6J mice, was associated with a minor reduction in food intake during the 6-h test and had no statistically significant effect on food or fluid intake during the 18-h post-test period or during a 6-h period the next day. The absence of large-scale or persistent nonspecific effects supports the use of the paradigm for screening of multiple solutions on the same animals. The reliability of the test is supported by positive correlations between repeated measurements of the same solution across substantial time intervals. Its ease of use, substantial reliability, and avoidance of water restriction make the test a very useful addition to screening tools in the field of gustation research.