[Amino acid chemoreception and motor activity in the frog Rana lessonae (Amphibia)].

The changes motor activity in the frog Rana lessonae in clean water depends on the type amino acids, stimulating chemoreceptors. Reactions orientations (as reaction of recognizing) in adult frog are caused by only amino acids constantly present in ponds water, while amino acids, only periodically appearing in ponds water, are not caused. Amino acids with more short chains of carbon atoms in the molecules (C3-C4) are more effective (with significance p < 0.

[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.

[The underwater EOG of the frog Rana temporaria to stimulation of the olfactory receptors with solutions of fragrances and amino acids].

Studies have been made on the effectiveness of 16 amino acids and 9 odorants in olfactory perception of the frog Rana temporaria. It was shown that the effectiveness of amino acids is close to that of odorants. Basic amino acids and cysteine were more effective than other amino acids.

[Behavioral reactions of the clawed toad Xenopus laevis to L- and D-isomers of amino acids].

Studies on the action of L- and D-isomers of amino acids upon motor activity in the clawed toad revealed that most effective among them are basic amino acids (all of them being essential) and hydrophobic amino acids (mainly essential ones). Positive correlation was found between the effectiveness of hydrophobic amino acids on the motor activity of animals and their effectiveness with respect to taste receptors. The data obtained indicate the role of the olfactory receptors in realization of the behavioural reactions of the clawed toads to amino acids.