Gamma-Aminobutyrylcholine

Abstract

As is generally admitted, acetylcholine is not the only cholinergic neurotransmitter, but other choline esters such as propionyl-¹, butyryl-², imidazoleacrylyl-³ and dimethylacrylyl-choline⁴ are also contained in the brain and other organs. On the paper chromatogram (solvent: butanol, ethanol, acetic acid and distilled water (8 : 2 : 1 : 3); colouring reagent: Dragendorff's reagent) of the base mixture, isolated as reineckate from trichloracetic acid extract of the dog brain, we noticed a spot around R _F 0.2, which appeared to be different from all the choline esters discovered to date. Among the choline esters synthesized by us, the existence of which in the organism is theoretically possible, gamma-amino-butyrylcholine also had R _F 0.2. (This ester was synthesized with the help of the Research Division, Daiichi Seiyaku Co., Tokyo. Melting point of the hydrochloride: 193° C. Analysis (per cent): found: C, 41.14; H, 9.12; N, 10.675; Cl, 26.99; calculated: C, 41.38; H, 8.64; N, 10.736; Cl, 27.15.) Besides this the methanol extract of the spot with R _F 0.2 cm. in the brain chromatogram gave a spot with R _F 0.9 when hydrolysed and chromatographed again (solvent: water-saturated phenol; colouring reagent: ninhydrin). This is close to gamma-aminobutyric acid (R _F 0.77).