EFFECT OF OLIGOPEPTIDES, CONTAINING L-PHE, L-TYR, L-TRP, L-HIS OR L-MET ON THE 2 IDENTIFIABLE GIANT-NEURONS OF AFRICAN GIANT SNAIL (ACHATINA-FULICA (FERUSSAC)

Abstract

Effects of about 90 oligopeptides, containing L-Phe, L-Tyr, L-Trp, L-His and L-Met, on the excitability of 2 identifiable giant neurons (the PON, periodically oscillating neuron; and the TAN, tonically autoactive neuron) of A. fulica Ferussac were examined. L-Lys-L-Phe-L-Tyr, L-Phe-L-Tyr and L-Phe-L-Trp showed an inhibitory effect on the PON. This effect was weaker than that of the same 3 peptides on the TAN. L-Phe-L-Phe, L-Phe-L-Phe-L-Phe, L-Tyr-L-Tyr and L-Tyr-L-Tyr-L-Tyr still showed a weak inhibitory effect on the TAN in a high concentration.