Reduction of rat brain levels of the endogenous dopaminergic proneurotoxins 1,2,3,4-tetrahydroisoquinoline and 1,2,3,4-tetrahydro-beta-carboline by cigarette smoke

1,2,3,4-Tetrahydroisoquinoline (TIQ) and 1,2,3,4-tetrahydro-beta -carboline (THPC) are two endogenous or exogenous dopaminergic proneurotoxicants supp osedly involved in the etiology of Parkinson's disease. We investigated whe ther the chronic administration of a twice daily dose of a cigarette smoke solution might modify the endogenous concentrations of TIO and THPC in rat brain. Using gas chromatography/mass spectrometry (GC-MS) we found a signif icant reduction in the brain levels of both proneurotoxins after 30 days of treatment. The reduction in the brain levels of both compounds was more si gnificant using Burley rather than Bright tobacco. These results suggest th at cigarette smoke may prevent the accumulation of these proneurotoxins in the brain, which corroborate the involvement of the reaction between both T IQ and THPC with some components of tobacco smoke as a neuroprotective mech anism for Parkinson's disease. (C) 2001 Elsevier Science Ireland Ltd. All r ights reserved.