Abstract

The substitution of the oxygen atom in the ethoxy group of choline by sulfur has little effect upon the "muscarine" action of the compound, but greatly intensifies the curare action and the, in some way, related "paralyzing nicotine action."

The substitution of sulfur for oxygen in the ethers of formocholine did not seem to greatly modify their physiological action. The thio compounds have a pronounced muscarine action which reached its maximum in the ethyl and n-propyl compounds. The thio compounds have a stimulating nicotine action which increases from the methyl-to the n-butylthio ether; higher homologues were not studied.

The experiments were not carried out in sufficient detail to permit of quantitative comparisons between the oxygen and sulfur ethers but there does not seem to be striking differences between them.

Thus in this class of compounds sulfur can replace oxygen; it was shown in the preceding paper of this series (8) that the nitrogen of analogous compounds may be replaced by sulfur without altering the nature of the action.

When oxygen is added to the sulfur in the thiomethylether (with the formation of sulfonyl compounds) the toxicity and physiological action are greatly reduced.