STIMULATION OF THE GERBILS GUSTATORY RECEPTORS BY SOME POTENTLY SWEETTERPENOIDS

The gerbil was investigated as a model for sweet taste among several h ighly sweet plant terpenoids and the sweet dihydroisocoumarin phyllodu lcin. Although the gerbil's chorda tympani nerve did not respond in el ectrophysiological experiments to rebaudiosides B and C, steviolbiosid e, and phyllodulcin, concentration-response curves were obtained for t he stimulatory sweeteners hernandulcin, mogroside V, periandrin III, r ebaudioside A, and stevioside. These compounds were more effective sti muli in the gerbil than sucrose, in the following order of potency: re baudioside A = stevioside = periandrin III > hernandulcin > mogroside V > sucrose. In conditioned-taste aversion studies, gerbils trained to avoid these five stimulatory compounds generalized an avoidance to su crose but not to hydrochloric acid, and except for the perception of a concomitant salty taste, our data show that these substances taste li ke sucrose to gerbils, as in humans. Support is thus provided for the potential involvement of this methodology to guide the purification of natural sweeteners from plant extracts.