Neurotransmitters in rats fed fumonisin B1.

Fumonisin B1, a toxin produced by Fusarium moniliforme, has been associated with a neurotoxic syndrome in horses known as equine leukoencephlomalacia. Previous investigations showed that F. moniliforme cultured on corn and incorporated into rat chow increased brain 5-hydroxyindoleacetic acid (5HIAA) and 5HIAA: serotonin (5HT) ratios in these animals. Therefore, this study was undertaken to determine whether fumonisin B1 would produce related neurochemical effects in the brain and pineal gland of male and female rats. Rats were fed fumonisin B1 at 15, 50, and 150 ppm for 4 weeks. No differences occurred in brain concentrations of norepinephrine, dopamine, 3,4-dihydroxyphenylacetic acid, 3-methoxytyramine, homovanillic acid, 5HT, 5HIAA, and the 5HIAA to 5HT ratios in either male or female rats, nor where there differences between the sexes. When compared across sexes, the norepinephrine to dopamine ratios were decreased (P < 0.05) in the 150-ppm-treated animals. This may suggest a fumonisin B1-induced imbalance in brain norepinephrine and/or dopamine. No differences were observed in pineal norepinephrine, 5HT, 5HIAA, and the 5HIAA to 5HT ratios. Since fumonisin B1 failed to duplicate the effects of the F. moniliforme-induced imbalances in 5HT and 5HIAA metabolism in the brains of rats, other mycotoxins from F. moniliforme may be responsible for these effects.