Sensitivities of single nerve fibers in the hamster chorda tympani to mixtures of taste stimuli.

Abstract

Responses of 3 groups of neural fibers from the chorda tympani of the hamster to binary mixtures of taste stimuli applied to the tongue were analyzed. The groups displayed different sensitivities to 6 chemicals at concentrations with nearly equal effects on the whole nerve. Sucrose-best fibers responded strongly only to sucrose and D-phenylalanine. NaCl-best and HCl-best fibers responded to 4 electrolytes: equally to CaCl2 and nearly equally to HCl. The former responded more to NaCl and the latter responded more to NH4Cl. The groups of fibers dealt differently with binary mixtures. Sucrose-best fibers responded to a mixture of sucrose and D-phenylalanine as if 1 of the chemicals was appropriately increased in concentration. They responded to a mixture of one and an electrolyte as if the concentration of sucrose or D-phenylalanine was reduced. NaCl-best fibers responded to a mixture as if it were a mixture of 2 appropriate concentrations of 1 chemical, or somewhat less. Responses of HCl-best fibers to mixtures were greater, approaching the sum of responses to components. The sensitivity of a mammalian taste receptor to 1 chemical apparently is affected by a second, which may or may not be a stimulus for that receptor. Some effects of taste mixtures in humans may be the result of peripheral processes.