Current(I)-voltage(V) relationships of the neuromembrane of an identifiable giant neurone of an African giant snail (Achatina fulica Férussac) in the presence of an inhibitory tripeptide, L-Lys-L-Phe-L-Tyr.

An inhibitory tripeptide, L-Lys-L-Phe-L-Tyr, caused membrane hyperpolarization of the TAN (tonically autoactive neurone) resulting in an elevated firing level. The tripeptide, however, did not markedly affect either the TAN I-V curve or the firing pattern obtained by transmembrane triangular current injection.