Salt as an oral irritant

Abstract

The temporal characteristics of oral irritation produced by NaCl and KCl were investigated in two experiments. Subjects were exposed to 0.4 and 0.8 M solutions of both salts at the rate of once per min for 15 min. No water rinses were allowed between sips. The results showed that the irritation produced by NaCl increased in intensity as a function of number of exposures. In contrast, the intensity of the salt taste remained approximately constant over the 15 min period. The relative contribution of irritation to the sensation of saltiness therefore increased over time. The same pattern of results was found for 0.8 M but not for 0.4 M KCl. The growth in perceived intensity of salt irritation with repeated exposures may be attributable to the phenomenon of ‘sensitization’ that is a characteristic of some nociceptive afferents. Overall, the results demonstrate that salts produce perceptible sensations of irritation at concentrations typically used in psychophysical studies of salt taste, and that this apparently non-gustatory component of saltiness vanes directly with both concentration and duration of exposure.