Estimation of the p and m isomers of hydroxyphenylacetic acid in mouse brain by a gas chromatographic procedure: their regional distribution and the effects of some drugs.

The mouse brain contains 12.5 and 4.1 ng/g of p- and m-hydroxyphenylacetic acids, respectively. The hydroxyphenylacetic acids were isolated by chromatography on DEAE-Sephadex A-25 and quantitated as their pentafluoropropionyl and hexafluoropropanol esters by use of a gas chromatograph equipped with an electron-capture detector. The highest concentrations of p- or m-hydroxyphenylacetic acids were observed in the caudate nuclei (27.9 and 8.7 ng/g, respectively) and olfactory tubercles (20.2 and 5.3 ng/g, respectively). The identities of the p- and m-hydroxyphenylacetic acids were further confirmed as a consequence of the reductions observed following monoamine oxidase inhibition or the increases observed in the appropriate acid following the parenteral administration of p- or m-tyramine.