A. Representative current trace recorded during perfusion of selected amino acids and amino acid derivatives. All substrates were added at 1 mM final concentration during the periods indicated by the black bars above the actual trace. 98 mM NaCl was used as the major salt. A voltage clamp mode with a holding transmembrane voltage of −50 mV was used during this recording. The single letter code corresponds to the canonical abbreviations for amino acids. Other abbreviations are: DOPA, L-3,4-dihydroxyphenylalanine; 5HTP, 5-Hydroxytryptophan; 5-HT. 5-Hydroxytryptamine; DA, dopamine; dM, D-Methionine; GABA, γ-Amino butyric acid; Tau, Taurine; OA, Octopamine; TA, Tyramine. B. Result of statistical evaluation of AeNAT5 induced currents (bars are the normalized average value for n > 3, different batches/oocytes). The neurotransmitters are indicated by gray font. C. Amino acid induced responses in control DW injected oocytes at the same amplitude and time scale as in panel A and insert.