Identification and Distribution of Phenylacetic Acid in the Brain of the Rat

Phenylacetic acid, the major metabolite of phenylethylamine, has been identified and quantitated in rat brain regions by capillary column high-resolution gas chromatography mass spectrometry. Its distribution is heterogeneous and correlates with that of phenylethylamine. The values obtained were (ng/g +/- SEM): whole brain, 31.2 +/- 2.7; caudate nucleus, 64.6 +/- 6.5; hypothalamus, 60.1 +/- 7.4; cerebellum, 31.3 +/- 2.9; brainstem, 33.1 +/- 3.3, and the "rest," 27.6 +/- 3.0.