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In order to investigate the effect of n-hexane and its metabolites on the Central Nervous System (CNS), we treated mice with n-hexane and 2,5-hexanedione (2,5-HD) by intraperitoneal (i.p.) administration. Gascromatographic mass spectrometric (GCMS) analyses of striatum and cerebellum revealed a consistent increase of 2,5-HD concentration at 0.5 and 2 hours after treatment and a decline to baseline levels at 24 hours. Traces of 2,5-HD were detected in the brain of control animals. Biochemical analyses revealed a precocious, short lasting, significant increase of striatal dopamine (DA) and homovanillic acid (HVA) levels. A significant increase of striatal synaptosomal DA uptake, suggesting a DA releasing effect on the dopaminergic terminals, was also observed. These results support the hypothesis of a possible role of n-hexane and its metabolites in inducing parkinsonism in humans and animals.

The possibility that age-related changes in amino acid levels in various rat brain areas might correlate with modifications of monoamine oxidase (MAO) activity, already found with aging, has been examined. Taurine, aspartic acid and glutamic acid levels were found to be unchanged or decreased with age, whereas GABA and glutamine concentrations increased or remained unchanged. Serine and glycine (except in pons-medulla) levels were found to be unaffected by age. The increase in total MAO activity with aging in some brain areas might contribute to the changes in amino acid levels. Likewise, the possible influence of age-induced changes in activity of various enzymes involved in H2O2 and NH3 detoxication and in amino acid biosynthesis on rat brain amino acid levels are considered. Oral administration of clorgyline or 1-deprenyl to young rats did not significantly modify the concentrations of most brain amino acids.