Human Salty and Bitter Taste Mechanisms
Principal Investigator: MARION ELIZABETH FRANK
Abstract: Mechanisms of salty and bitter chemoreception in humans are not well understood, in part because compounds that block these tastes have not been available; and importantly, because animals models for salty and bitter taste perceptions are not fully applicable. Chlorhexidine glueonate, a bis-biguanide antiseptic, and weak cathodal electric currents greatly decrease salty and bitter tastes. Besides adaptation, no other experimental manipulations are known to have comparable effects in humans. Chlorhexidine is very bitter, but not salty. Chlorhexidine binds strongly to tissue, which may be related to its unique bis-eationic structure, giving it a long-lasting effect. Human psychophysical experiments are proposed[unreadable] Cation/anion specificity of salty-bitter taste inhibition by 3 levels of ehlorhexidine and 2 levels of weak eathodal current is studied with experiments utilizing rating of taste intensity and taste-quality identification of equi-intense stimuli. Taste- stimulus identification is studied after treatment with two levels of ehlorhexidine with measures of information transferred (in bits). Tlo, a measure of consistency, is eomputed from a matrix of 10 replicate identifications of 10 stimuli. Forty-five Tes, measures of stimulus diseriminability, are eomputedfor all possible stimulus pairs. This "confusion-matrix" methodology is an efficient and objective method for determining discriminability of multiple stimuli. Various salt and bitter stimulus combinations are included in sets of equi-intense stimuli to test the hypothesis that chlorhexidine affects ionic bitter stimuli more than non- ionic bitter stimuli. Two levels of chlorhexidine are used with concentration series of suerose, NaCI, citric acid and quinine.HC! to address the nature of the inhibition. Effects of adaptation to other bitter stimuli on the bitter taste of chlorhexidine are studied to establish whether one mechanism of action of chlorhexidine could involve its binding to a subset of bitter receptors. The experiments address the general hypothesis that transduction of salty stimuli is unitary, depending on ion-transport pathways; but bitter transduction is multiple, including ionic and non-ionic mechanisms. Greater understanding of gustatory perceptual processing in humans may lead to better management of taste disorders such as distressful salty-bitter dysgeusias and excessive salt intake.
Funding Period: 2003-01-08 - 2008-12-31
more information: NIH RePORT
- Effects of selective adaptation on coding sugar and salt tastes in mixturesMarion E Frank
Department of Oral Health and Diagnostic Sciences, Division of Periodontology, Center for Chemosensory Sciences, School of Dental Medicine, University of Connecticut Health Center, Farmington, CT 06030 1715, USA
Chem Senses 37:701-9. 2012..Furthermore, like odors, stronger and recent tastes are emphasized in dynamic experimental conditions replicating natural situations...
- Time and intensity factors in identification of components of odor mixturesMarion E Frank
Department of Oral Health and Diagnostic Sciences, Division of Periodontology, Center for Chemosensory Sciences, School of Dental Medicine, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030 1715, USA
Chem Senses 35:777-87. 2010..Rapid selective adaptation and mixture component suppression manipulate effective intensity to promote emergence of characteristic odor qualities in dynamic natural settings...
- Characteristic component odors emerge from mixtures after selective adaptationHolly F Goyert
Department of Psychology, Cornell University, Ithaca, NY, USA
Brain Res Bull 72:1-9. 2007....
- Regional specificity of chlorhexidine effects on taste perceptionRuchi Grover
Department of Biology, University of Hartford, CT 06117, USA
Chem Senses 33:311-8. 2008..The current results are the first to suggest that there may also be distinct, regionally specific populations of NaCl-taste receptors in humans...
- Cracking taste codes by tapping into sensory neuron impulse trafficMarion E Frank
Center for Chemosensory Sciences, Department of Oral Health and Diagnostic Sciences, University of Connecticut Health Center, Farmington, CT 06030 1715, United States
Prog Neurobiol 86:245-63. 2008..Establishing the information afferent neurons traffic to the brain about natural taste stimuli imbedded in dynamic complex mixtures will ultimately "crack taste codes."..
- Salt taste inhibition by cathodal currentThomas P Hettinger
Center for Chemosensory Sciences, Division of Periodontology, Department of Oral Health and Diagnostic Sciences, School of Dental Medicine, University of Connecticut Health Center, Farmington, CT 06030 1715, USA
Brain Res Bull 80:107-15. 2009..Cathodal current may selectively inhibit salty and bitter-salty tastes for which proximal stimuli are cations...
- Taste coding after selective inhibition by chlorhexidineMiao Fen Wang
John B Pierce Laboratory, Yale University School of Medicine, New Haven, CT 06519, USA
Chem Senses 34:653-66. 2009..Discrimination among prototypic stimuli with varying strengths was consistent with a gustatory system that evaluates a small number of independent tastes...