The effect of alcoholism on salsolinol and biogenic amines in human brain

Abstract

Chronic alcoholics with a well documented history of alcohol abuse were divided at autopsy into two groups, intoxicated alcoholics (IA, with blood ethanol levels) and sober alcoholics (SA, without blood ethanol levels). Norepinephrine (NE), 4-hydroxy-3-methoxyphenyl-glycol (HMPG), 5-hydroxyindoleacetic acid (5-HIAA), dopamine (DA), salsolinol (SAL) and methylated salsolinol (M-SAL) in caudate nucleus and putamen from the two groups of alcoholics and an age-matched control group were analysed with gas chromatography-mass spectrometry. HMPG was significantly increased in the brains of the alcoholics compared to controls (IA, P < 0.001 and SA, P < 0.05) indicating an increased NE turnover in the brains of alcoholics. 5-HIAA, the major 5-hydroxytryptopan (5-HT) metabolite, was increased in the caudate nucleus from SA ( P < 0.05) compared to controls and IA. This could be interpreted as an increased turnover of 5-HT at abstinence. SAL can be formed from DA and acetaldehyde and/or pyruvate. SAL was found in all brains studied. The levels were about 1% of the dopamine concentrations. SAL had a tendency to be increased in brains of IA compared to control brains. The most remarkable finding was that SAL was significantly decreased in both the caudate nucleus and putamen from SA compared to controls and IA. M-SAL showed tendencies in the same directions as SAL. DA did not show any significant changes, but tended to be lower in SA. A hypothetical explanation for the low SAL levels in the SA could be a decreased brain energy metabolism in alcoholics resulting in decreased pyruvate production and thus decreased SAL formation. In alcoholics with ethanol in their blood an additional source of SAL could be acetaldehyde (derived from ethanol) and DA.