Cross-adaptation and bitterness inhibition of L-Tryptophan, L-Phenylalanine and urea : further support for shared peripheral physiology


Autoria(s): Keast, Russell; Breslin, Paul A. S.
Data(s)

01/01/2002

Resumo

A previous study investigating individuals' bitterness sensitivities found a close association among three compounds: L-tryptophan (L-trp), L-phenylalanine (L-phe) and urea (Delwiche et al., 2001, Percept. Psychophys. 63, 761-776). In the present experiment, psychophysical cross-adaptation and bitterness inhibition experiments were performed on these three compounds to determine whether the bitterness could be differentially affected by either technique. If the two experimental approaches failed to differentiate L-trp, L-phe and urea's bitterness, then we may infer they share peripheral physiological mechanisms involved in bitter taste. All compounds were intensity matched in each of 13 subjects, so the judgments of adaptation or bitterness inhibition would be based on equal initial magnitudes and, therefore, directly comparable. In the first experiment, cross-adaptation of bitterness between the amino acids was high (>80%) and reciprocal. Urea and quinine-HCl (control) did not cross-adapt with the amino acids symmetrically. In a second experiment, the sodium salts, NaCl and Na gluconate, did not differentially inhibit the bitterness of L-trp, L-phe and urea, but the control compound, MgSO4, was differentially affected. The bitter inhibition experiment supports the hypothesis that L-trp, L-phe and urea share peripheral bitter taste mechanisms, while the adaptation experiment revealed subtle differences between urea and the amino acids indicating that urea and the amino acids activate only partially overlapping bitter taste mechanisms.<br />

Identificador

http://hdl.handle.net/10536/DRO/DU:30004137

Idioma(s)

eng

Publicador

Oxford University Press

Relação

http://dro.deakin.edu.au/eserv/DU:30004137/keast-crossadaptationandbitterness-2002.pdf

http://dro.deakin.edu.au/eserv/DU:30004137/n20062263.pdf

http://dx.doi.org/10.1093/chemse/27.2.123

Direitos

2002, Oxford University Press

Palavras-Chave #adaptation #psychophysics #bitter taste #amino acids #bitter receptors #taste perception #bitter blocking
Tipo

Journal Article