The effect of gamma-aminobutyric acid on synaptic transmission in autonomic ganglia

The presence in the mammalian brain and spinal cord of “Factor I ” which possesses some of the properties of an inhibitory transmitter have been reported by Florey and McLennan (1955a, b). They found that purified extracts of Factor I in low concentrations could block synaptic transmission in the inferior mesenteric and stellate ganglia of cats. No effect could be obtained in the superior cervical ganghion. Bazemore et al (1956, 1957) reported that the total activity of Factor I preparations could be accounted for by their gamnu.a-aminobutyric acid (GABA) content. This finding was based on the assay developed by Elliott and Florey (1956) in which Factor I extracts were tested on th