[The submerged electro-olfactogram of the clawed toad Xenopus laevis]

Relative effectiveness of 17 amino acids solutions (5 x 10(-4) mol/l) for olfactory receptors of the clawed frog has been determined by measuring underwater (EOG) amplitude in ventro-medial and lateral areas of the nose. It was revealed that hydrophilic amino acids (cysteine, glycine, threinine, tyrosine) produced larger EOG in ventro-medial area as compared with hydrophobic ones (alanine, valine, leucine, phenylalanine, proline, tryptophan). Hydrophobic amino acids were more effective in lateral area. It was shown that olfactory receptors in ventro-medial area but not in the lateral one in regard to stimulating amino acids were similar to olfactory receptors of the frog Rana temporaria. Amino acids which induced the greatest increase of mobility in the frog Xenopus laevis (the reactions to these amino acids were similar to the effects of food stimuli) produced the largest EOG in ventro-medial area.