Anterior tongue stimulation with amiloride suppresses NaCl saltiness, but not citric acid sourness in humans.

Suppression of the saltiness of NaCl solutions by amiloride, a sodium channel blocker, has previously been reported a number of times in humans. This suppression was seen with techniques that involved stimulation of small areas of the tongue. It was not certain, however, whether amiloride would suppress saltiness with stimulation of a much larger area of the tongue; one published study, in fact, found negative results with whole mouth stimulation. For this study, eight subjects dipped a large part of the anterior portion of the tongue into a 10-ml sample of NaCl solution, or a NaCl and amiloride solution, and reported its magnitude of saltiness intensity. The results show that amiloride suppressed the saltiness of NaCl when a large area of the anterior tongue was stimulated. Consistent with previous studies, there was individual variability across subjects in this suppressive effect of amiloride. This study also used this method to test the effects of amiloride on the sourness of citric acid, which was not expected to be affected. No suppression of sourness was seen with amiloride.