High-Throughput Screens for Assessing Taste Sensitivity in Mice

P.I.:  John I. Glendinning¹
Co-P.I.:  Alan C. Spector²

Location and Contact Information:

¹Department of Biological Science,
Barnard College
Columbia University
3009 Broadway
New York, NY 10027
phone: 212-854-4749
email: jglendinning@barnard.edu

²Department of Psychology,
University of Florida,
Gainesville, FL 32611
phone: 352-392-0601, x288
email: spector@psych.ufl.edu

Description:  Humans suffer from a variety of taste disorders that impair their ability to acquire essential nutrients, regulate secretion of digestive enzymes, and enjoy one of life's simple pleasures: eating. As there are few effective therapies for these disorders, the impending comprehensive analysis of the mouse genome offers great promise for helping fill this void. The ability of taste geneticists to identify genetically-based alterations in murine taste sensitivity has been impeded by the absence of a high-throughput screening protocol. Over the last decade, taste psychophysicists have developed a high-throughput procedure for assessing taste sensitivity in rats, called brief-access taste testing. Our goal is to adapt this reliable, easy-to-use, and efficient procedure to mice.

Procedure:  Mice are provided with access to a single taste stimulus during brief (e.g., 5 sec) trials, and licking responses are measured with an automated gustometer (see below). Using this device, one can present several taste stimuli (e.g., different concentrations of sucrose) during a 30-min test session in a randomized order, derive a robust concentration-response function, and be relatively confident that the licking responses are under orosensory control and not confounded by postingestive effects of the taste stimulus. To this end, a secondary screen will be developed for testing wild-type and mutant C57BL/6 mice. Because this screen will be conducted with an expansive array of concentrations of several taste stimuli (e.g., quinine, NaCl, and sucrose), it will be able to detect gross and subtle alterations in taste sensitivity in either direction. On the basis of the knowledge gained through the development of the secondary screen, critical concentrations will be chosen for a primary screen to provide a relatively quick assessment of taste sensitivity. Outliers identified with the primary screen can be subjected to the secondary screen for confirmation. A normative data-base for both screens will be established and made available to the scientific community. The assay procedures developed will be applicable by a single laboratory technician with limited experience.

Illustration of a gustometer, similar to the one we are using. Once a mouse is placed in the test chamber, a shutter (not shown) will open, providing the mouse with access to a spout though a small slit (see right diagram). This gustometer can automatically position up to 8 different taste stimuli in front of the slit by moving the stimulus delivery system laterally in precise steps (see left diagram). All licks to a drinking spout will be recorded by a high frequency AC contact circuit (not shown). The dedicated computer system, which controls the stimulus delivery system and records licks, is not shown.

Selected references illustrating use of the brief-access taste test in rats:

1. Spector, A. C., Redman, R. and Garcea, M. (1996). The consequences of gustatory nerve transection on taste-guided licking of sucrose and maltose in the rat. Behavioral Neuroscience 110, 1096-1109.

2. Markison, S., St.John, S. J. and Spector, A. C. (1995). Glossopharyngeal nerve transection does not compromise the specificity of taste-guided sodium appetite in rats. American Journal of Physiology 269, R215-R221.

3. St. John, S. J., Garcea, M. and Spector, A. C. (1994). Combined, but not single, gustatory nerve transection substantially alters taste-guided licking behavior to quinine in rats. Behavioral Neuroscience 108, 131-140.