Effects of amiloride on gustatory quality descriptions and temporal patterns produced by NaCl

The amiloride-sensitivity of perceived taste qualities and time-intensity patterns for NaCl, and interactions between amiloride and NaCl as taste stimuli, were explored using caffeine as the control treatment. NaCl at 100, 250 and 500 mM, dissolved in 10 or 100 microM amiloride, or in caffeine concentrations matched to the amiloride taste, was flowed over 39.3 mm2 of the anterodorsal tongue for 4 s using a closed stimulus delivery system. Amiloride, caffeine and NaCl in H2O were also presented. It was found that NaCl-amiloride mixtures were most frequently described as salty, with the incidence of salty descriptions directly associated with NaCl concentration but not significantly associated with the presence or concentration of amiloride. Amiloride in H2O was called 'bitter', and the incidence of bitter descriptions was significantly associated with the presence of amiloride. The perceived temporal patterns varied with NaCl concentration but did not change with the presence of amiloride, except for an increase in perceived duration. No evidence was found for a dependence upon specific amiloride-sensitive mechanisms of human description of NaCl as salty or of gustatory temporal patterns evoked by NaCl.