Abstract
The gustatory responses from the chorda tympani nerve of the Mongolian gerbil, Meriones unguiculatus, were tested with saccharin and some closely related compounds. Only two compounds, saccharin and 6- chlorosaccharin, stimulated the gerbil's taste receptors to any degree and in the same order in which they are sweet to man, saccharin greater than 5-chlorosaccharin. Those compounds which are tasteless to man did not stimulate and include N-methyl saccharin, phthalimide, and O- sulfobenzoic acid. These nonstimulating derivatives did not inhibit the saccharin electrophysiological response. The saccharin taste response pH optimum is from 5 to 8. At pH 7 and 8, saccharin is fully ionized and is binding to the receptor site by an anionic mechanism. Kinetic plots of the taste response at pH 7 indicate that saccharin is forming 1:1 complexes with it. In addition, mixtures of saccharin and sucrose stimulate in such a manner as to suggest that they are interacting at different receptor sites.
