Effects of amiloride on salt taste in humans

Amiloride reduces several responses of the taste system to NaCl. These effects are crucial support for the ion transport theory of salt taste. Here, three experiments tested for the inhibitory effect of amiloride on salt taste in normal, whole-mouth tasting in humans. There was no evidence that amiloride reduces the saltiness of NaCl when used as a pretreatment, mixed into solution with NaCl, or both. In a fourth experiment, pretreating the tongue with amiloride-soaked filter paper and presenting NaCl on filter paper within the treated area also had no effect on saltiness. In addition, amiloride, a bitter compound, did not suppress the taste of sucrose, and caffeine did not enhance the taste of NaCl. These results suggest the ion transport theory of NaCl taste needs to be modified or extended to account for normal whole-mouth tasting of NaCl in humans.