Effects of chlorhexidine on human taste perception

Chlorhexidine, a bis-cationic biguanide antiseptic, greatly reduces the per ceived intensity of the salty prototype sodium chloride and may prove to be an important probe of mechanisms that underlie the human salty taste quali ty, Chlorhexidine, which tastes bitter, also reduces quinine hydrochloride taste intensity, but neither sweet sucrose nor sour citric acid is affected . Perceptual intensity rating and quality identification were measured for human subjects before and for 30 min following treatment with 1.34 mM chlor hexidine gluconate. In one experiment, test stimuli were the taste-quality prototypes; in a second experiment, stimuli were series of sodium, halide a nd sulfate salts. Experiment 1 showed a single 3-min chlorhexidine treatmen t resulted in reductions in taste intensity that persisted for at least 30 min. Experiment 2 showed a single 2-min chlorhexidine treatment reduced per ceptual intensities of halide and sulfate salts except those with divalent cations. Chlorhexidine impaired identification of the salty quality and pro duced a bitter quality in nonbitter salts and impaired identification of th e bitter quality of quinine, but not bitter salts. The specific effect of c hlorhexidine on the bitterness of quinine suggests it may bind to the same receptor as quinine. The ability of chlorhexidine to specifically disrupt s altiness of a wide range of salts is consistent with proposed peripheral tr ansduction mechanisms for the salty quality that involve transepithelial io n transport. (C) 2001 Elsevier Science Inc. All rights reserved.