title: Inhibitory effect of tripeptides containing L-Phe-L-Tyr on neuronal excitability.
abstract: Eight tripeptides containing L-Phe-L-Tyr were synthesized, and their effects on the excitability of a giant neurone (tonically autoactive neurone, TAN), identified in the suboesophageal ganglion of an African giant snail (Achiatina fulica Férussac), were examined. Of these tripeptides, the following three showed a marked inhibitory effect: L-Glu-L-Phe-L-Tyr (most effective; critical concentration: 3 X 10(-6)--10(-5) M), Gly-L-Phe-L-Tyr and sarcosine-L-Phe-L-Tyr. The TAN inhibition caused by L-Glu-L-Phe-L-Tyr was not due to an increased membrane permeability to chloride ions.
mesh_terms: D000818:Animals; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000187:drug effects*; D009842:Oligopeptides / Q000494:pharmacology*; D010649:Phenylalanine / Q000494:pharmacology*; D012908:Snails; D014443:Tyrosine / Q000494:pharmacology*
chemical_list: D009842:Oligopeptides; D014443:Tyrosine; D010649:Phenylalanine