Blocking and Protecting Actions of Amines and Ammonium Compounds on a Crustacean Synapse

Summary

This paper describes the effects of various amines and ammonium compounds on synaptic transmission in the central nervous system of the crayfish.

In the series from butyl to octyl amine, the activity of the drug in blocking synaptic transmission increases with the length of the alkyl side chain. Dodiecyl amine shows greater activity than octyl amine. The corresponding alkyl methylamines and dimethyl-amines show a similar increase. The trimethylammonium series shows no blocking activity until the dodecyl compound is reached. The amyl trimethylammonium compound is unique in showing a consistent facilitation of synaptic transmission.

The ability of sub-threshold doses of these drugs to protect the preparation against the blocking action of nicotine reaches a maximum with the octyl compounds. The protecting activity of the trimethylammonium series is generally weaker than that of the other compounds. Although the dodecyl compounds show only a trace of protection against nicotine, this weak protection is shown at very high dilution.