The effects of p-chlorophenylalanine and ethanolamine-O-sulphate in an animal test of anxiety.

p-Chlorophenylalanine, which produces a depletion of brain 5-HT concentration, had effects qualitatively similar to those previously found with chronic chlordiazepoxide and with acute ethanol in the social interaction test of anxiety. This result is compatible with the idea that a reduced turnover of 5-HT is important in anxiety reduction. On the same test, ethanolamine-O-sulphate, which raises brain gamma-aminobutyric acid, was without effect, suggesting raised concentrations of this acid are not essential for anxiety reduction.