Anion size of sodium salts and simple taste reaction times.

Simple taste reaction times (RT) and taste intensities were measured in adult humans for 100-mM aqueous solutions of sodium chloride, acetate, glutamate, ascorbate, and gluconate flowed over the anterodorsal tongue with a closed liquid delivery system. Results from 12 subjects showed a significant increase in RT with molecular weight of the tastant, and a correlation of 0.941 between RT and the square roots of anionic weights. A multiple regression analysis controlling for perceived taste intensity indicated that RT increased linearly with the square root of the anionic weight. These findings support a model that includes both the permeability of ions through the tight junctions between the taste receptor cells of fungiform papillae taste buds and the effects of ions at apical portions of the receptor cells. They also suggest that gustatory transduction of sodium salts in humans normally involves intercellular spaces of taste buds as part of the functional sensory structures, in addition to individual taste receptor cells.