Effect of long-term administration of manganese on biogenic amine levels in discrete striatal regions of rat brain.

The effect of long-term manganese exposure of rats on biogenic amine levels in striatal brain regions is described. Four groups of male Sprague-Dawley rats received manganese as MnCl2 continuously in the drinking water for 60, 100, 165 and 265 days, respectively. Discrete regions within the caudate-putamen were punched out. Dopamine, 3,4-dihydroxyphenylacetic acid, homovanillic acid, serotonin and 5-hydroxyindoleacetic acid were determined by high performance liquid chromatography with electrochemical detection. Rats exposed for 60 and 165 days showed significantly increased levels of dopamine and 3,4-dihydroxyphenylacetic acid in discrete regions of the dorsal caudate-putamen. The affected regions were possibly not identical in the two age groups but they were adjacently situated. These alterations were not found in rats exposed for 100 or 265 days.