EFFECT OF AMILORIDE ON SUPRATHRESHOLD NACL, LICL, AND KCL SALT TASTE IN HUMANS

The purpose of this study was to investigate normal Variances in the r esponse magnitudes of suprathreshold concentrations of NaCl, LiCl, and KCI salts and amiloride on the anterior human tongue. Random equimola r concentrations of salt solutions were delivered to spatially matched flow chambers of 20 volunteers at 3 different sessions. A cross-modal magnitude matching procedure was used to scale salt taste-intensity j udgments. After each salt test, amiloride (100 mu m) was delivered for 5 min and the test was repeated. A least-square regression analysis o f each subject's function between log molar concentration and log resp onse demonstrated that every subject scaled the dynamic range of salts . There were no differences in either the mean regression or intercept among the 3 salts. Repeated-measures analysis demonstrated a statisti cal effect of amiloride on the before/after difference in the regressi on (p = 0.02) and intercept (p < 0.0001) of NaCl and LiCl functions. P ostamiloride NaCl and LiCl coefficient of variance of response was inc reased. Amiloride had no effect on the before/after difference in the regression and intercept of KCl power functions or the variance of res ponse. The results suggest that, after amiloride, NaCl and LiCl suprat hreshold salt taste intensities are reduced, but there are individual variabilities of reduced intensity that are never completely eliminate d. (C) 1997 Elsevier Science Inc.