Stimulation of the gerbil's gustatory receptors by artificial sweeteners.

Some electrophysiological and behavioral taste experiments have been undertaken to determine how the Mongolian gerbil responds to artificial sweeteners. In the electrophysiological experiment only fourteen of twenty-one sweeteners produced neural responses. The most potent compound was L-4'-cyano-3-(2,2,2-trifluoroacetamido)succinanilic acid. Halogenated derivatives were more potent stimuli than non-halogenated ones. D-Tryptophan was stimulatory while L-tryptophan was not. The electrophysiological responses to sucrose were not inhibited by the presence of non-stimulating sweeteners nor were the responses to D-tryptophan inhibited by L-tryptophan. All the compounds that were stimulatory electrophysiologically were used in the behavior experiment. Using conditioned taste aversion, the gerbils responded to 5 of the compounds as sweet, one as sweet-salty, two as sweet-bitter, one as sour and one as bitter. In addition, 3 compounds were drunk equally by all groups suggesting that they were tasteless or possessed some unknown taste quality. A correlation was found between the efficacy (Kd) of the sweet-tasting compounds (pure sweet or mixed sweet) and the sweetness ranking by humans.