In vivo and in vitro electrophysiological monitoring of rat neocortical activity after dietary fumonisin exposure

Corn pellets, containing 30 mg/kg bw/day fumonisin B₁ (FB₁) or containing no FB₁ were fed in two series of experiments to rats. Spontaneous and evoked potentials were measured in the neocortex both in vivo and in vitro in “corn fed control” rats and in rats after a five day dietary exposure to FB₁. The FB₁ content of corn was quantitated by HPLC. Auditory evoked potentials recorded in vivo on freely moving animals after feeding a corn diet containing FB₁ for 5 days revealed a highly significant 20–60% decrease in the primary and mid-latency components; cortex slices in vitro showed a reduced excitability both in standard artificial cerebrospinal fluid (ACSF) solution and in a 4-aminopyridine induced epilepsy model. Spontaneous epileptic discharges after FB₁ exposure had an increased latency, decreased frequency, longer duration and modified signal forms. Altered excitability and seizure susceptibility of the neocortex after fumonisin exposure are suspected to be associated with modified signal transmission. These changes may be due to concurrent effects of possible liver and renal toxicity or partly of nutritional deficiencies. This revised version was published online in June 2006 with corrections to the Cover Date.