The effect of low-level deoxynivalenol on neurotransmitter levels measured in pig cerebral spinal fluid.

Deoxynivalenol (DON) is one of the major mycotoxins produced by Fusarium fungi, and is known to affect feeding behaviour in economically important animals. In this study the effect of low-level DON on cerebral spinal fluid (CSF) neurotransmitter concentrations, as a reflection of altered brain activity, was investigated in swine. Animals were given repetitive doses (6) at 30 min intervals, either intravenously (iv) (10 micrograms/kg) or intragastrically (ig) (30 micrograms/kg). Serial CSF samples were collected via a novel permanent indwelling catheter placed intracerebrally, and changes in catecholamine levels monitored. Results showed a rapid and sustained increase in 5-hydroxyindoleacetic acid (5HIAA) occurred following ig administration, remaining elevated for up to 20 hr post-dosing, and to a lesser extent after iv dosing, lasting up to 6 hr post-dosing. This was indicative of increased CNS serotoninergic activity and indicative to the theory that links elevated brain serotonin turnover to a decrease in feed intake. Also observed were alterations in dopamine (DA) metabolism. Following ig dosing, a delayed increase in homovanillyl alcohol (HVOL) suggested an enhancement of the dopaminergic response occurred as serotoninergic activity diminished. Following iv dosing, a rapid drop in homovanillic acid (HVA) levels alluded to a more direct toxic effect, possibly acting as an inhibitor of DA-metabolizing enzymes.