Migration of tetrahydroisoquinoline, a possible parkinsonian neurotoxin, into monkey brain from blood as proved by gas chromatography—mass spectrometry

Abstract

1,2,3,4-Tetrahydroisoquinoline (TIQ) was quantitated by use of gas chromatography—mass spectrometry in brains and livers of marmosets which showed parkinsonism after daily subcutaneous injection of TIQ. TIQ showed greatly increased levels in the brains and livers of the TIQ-treated marmosets, with no detectable metabolites of TIQ. TIQ was present as an endogenous amine in the brains and livers of saline-treated marmosets at very low concentrations. It thus seems that TIQ can pass easily through the blood—brain barrier but cannot be metabolized in the brain or the liver. It is possible that TIQ accumulated in the brain may produce parkinsonism.