title: Citrate ions enhance taste responses to amino acids in the largemouth bass.
abstract: The glossopharyngeal (IX) taste system of the largemouth bass, Micropterus salmoides, is highly selective to amino acids and is poorly responsive to trisodium citrate; however, IX taste responses to specific concentrations of L- and D-arginine and L-lysine but not L-proline were enhanced by citrate but not sodium ions. Binary mixtures of L-arginine (3 x 10(-4)M and 10(-3)M) or D-arginine (10(-3)M) + trisodium citrate (10(-3)M; pH 7-9) resulted in enhanced taste activity, whereas binary mixtures of higher concentrations (10(-2)M and 10(-1)M) of L- or D-arginine + 10(-3)M trisodium citrate were not significantly different from the response to the amino acid alone. Under continuous adaptation to 10(-3)M citrate, taste responses to L-arginine were also enhanced at the identical concentrations previously indicated, but responses to 10(-2)M and 10(-1)M L-arginine were significantly suppressed. Under continuous adaptation to 10(-2)M L-arginine, taste responses to 10(-2)M, 10(-1)M, and 10(0) M citrate were significantly enhanced. Cellular concentrations of both citrate and amino acids in prey of the carnivorous largemouth bass are sufficient for this taste-enhancing effect to occur naturally during consummatory feeding behavior. Citrate acting as a calcium chelator is presented as a possible mechanism of action for the enhancement effect.
authors: Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, USA.
authors: K
authors: K
authors: Ogawa
authors: J
authors: J
authors: Caprio
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects / Q000502:physiology; D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D001120:Arginine / Q000494:pharmacology; D001492:Bass / Q000502:physiology*; D019343:Citric Acid / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D005247:Feeding Behavior / Q000502:physiology; D005930:Glossopharyngeal Nerve / Q000502:physiology; D008239:Lysine / Q000494:pharmacology; D011392:Proline / Q000494:pharmacology; D013652:Taste Threshold / Q000187:drug effects* / Q000502:physiology*
chemical_list: D000596:Amino Acids; D019343:Citric Acid; D001120:Arginine; D011392:Proline; D008239:Lysine