Mode of Action of Aliphatic Amino Acids on Cortical Synaptic Activity

Abstract

Conclusion

Several types of electrophysiological tests have been applied to the analysis of the pharmacological actions of amino acids. Only the ω-amino acids have been found to have pronounced synaptic effects among the available C₂ to C₈ compounds. The α-amino acids, with the exception of glycine which has its amino group in the terminal position, are not synaptically active. Synaptic action is reduced or abolished by conversion to the α, ω-diamino compound. The ω-amino acids all act to blockade synapses, but quantitative and qualitative differences characterize the compounds of different carbon length. The C₂ to C₅ compounds block predominantly the depolarizing, excitatory synapses, while the C₆ and C₈ ω-amino acids block selectively the hyperpolarizing, inhibitory synapses. Within each group there are quantitative differences in effectiveness of selective action. The findings provide a new series of pharmacological tools for the analysis of the molecular structure and organization of central nervous synapses.