Specific Amino Acid Binding to Membrane Fractions of Carp Taste Epithelium

The gustatory system of the carp, Cyprinus carpio, is highly sensitive to amino acid stimuli. The amino acid receptor mechanisms have been characterized in previous electrophysiological studies to have thresholds in the nM range. Self- and cross-adaptation experiments have indicated independent taste receptors for the L-isomers of alanine, glutamate, aspartate, proline, and cysteine, and for glycine betaine [1]. Receptor adaptation with each of these amino acids did not affect taste responses to the other amino acids. This study of Marui et al. [1] suggested the presence of six different types of high affinity amino acid receptors in the taste cell membranes of the carp.