Gas chromatographic/mass spectrometric evidence for the identification of 6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline as a normal constituent of rat brain. Its quantification and comparison to rat whole brain levels of dopamine.

Gas chromatographic/mass spectrometric data are presented which demonstrate the presence of 6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (DHTIQ) as a normal constituent of rat brain. The level of DHTIQ was calculated to be 10.0 +/- 3.0 ng/g wet weight (+/- S.D., N = 9) of brain tissue while the level of dopamine (DA) was measured as 1.22 +/- 0.22 microg/g (N = 14). The ratio of DHTIQ:DA was thus observed to be approximately 1:100. The possible formation of DHTIQ in alcoholism and schizophrenia is discussed.