Olfactory receptor neurons (ORNs) in aquatic species are known to respond to various groups of water-borne odorants such as bile acids, nucleotides and amino acids. In previous studies it has been shown that a subset of ORNs in larval Xenopus laevis can be activated by amino acids. To better understand the extent of the amino acid detection capabilities of larval Xenopus laevis, in the present work we investigated the sensitivity of individual ORNs to amino acids using calcium imaging in acute olfactory epithelium slices. We measured dose-response curves of several amino acids (L-methionine, L-arginine and L-lysine) and thoroughly compared detection thresholds and EC50-values of individual ORNs.

[Funded by Deutsche Forschungsgemeinschaft through the DFG- Research Center for Molecular Physiology of the Brain]