ETHERS OF CHOLINE AND ALLIED COMPOUNDS

1. The phenyl ether of α-methyl choline caused only a rise of blood pressure. The introduction of a methyl, ethyl, iso -propyl or amino group into the phenyl ether of α-methyl choline diminished the pressor (nicotine-like) action; the iso -propyl compound was the least active. 2. β-(o-toloxy)-ethyl triethylammonium bromide and analogous triethyl compounds (including sulfhydro-triethyl ammonium iodide) prevented the rise of blood pressure caused by the phenyl ether of choline and its derivatives and tetramethylammonium bromide, acetyl-α-methyl choline and nicotine, i.e., these triethyl compounds have a "paralyzing nicotine action." 3. The methyl and ethyl ethers of β-methyl choline caused only a fall of blood pressure; the ethyl ether was five to ten times as active as the methyl ether. The fall of blood pressure was prevented by atropine; neither of the compounds caused a rise of blood pressure after atropine. Small doses of the iso -propyl ether caused a fall of blood pressure; larger doses caused a fall followed by a rise. After atropine this compound caused only a rise of blood pressure. 4. The ethers of the triethylammonium compounds have no "muscarine" or "stimulating nicotine" actions; they have however a "paralyzing nicotin" action. 5. The effects upon the blood pressure of a number of heterocyclic compounds are described; most of these caused a rise of blood pressure but those studied were not very active in this respect.