Taste responses of the facial and glossopharyngeal nerves to amino acids in the rainbow trout

No significant differences were noted between responses of rainbow trout On corhynchus mykiss facial and glossopharyngeal nerves to 15 amino acids. Nin e of these amino acids tested at 10(-2)M were stimulatory, whereas only two tested at 10(-3)M were effective gustatory stimuli. For both nerve systems , less than or equal to 10 M-3 L-proline was the most stimulatory amino aci d, with an estimated threshold of 10(-7) M: however. L-alpha -amino-beta -g uanidino-propionic acid (estimated threshold of 3 x 10 3 hr). was the most potent compound at 10(-2)M. These results indicate that the same amino acid s activate taste buds innervated by facial and glossopharyngeal nerves, res pectively. and suggest that the same amino acids can be important in chemos ensory feeding behaviour in the rainbow trout. (C) 2001 The Fisheries Socie ty of the British Isles.