Amygdalar injection of FeCl3 causes spontaneous recurrent seizures

Rats were microinjected with a 100 mM aqueous solution of ferric chloride into the left amygdaloid body. Behavior was observed and depth electroencephalograms were recorded over the 30 days following injection. All of the FeCl3-injected rats developed isolated epileptiform discharges from the ipsilateral amygdala soon after injection. Within 5 days epileptiform discharges were arising as well from the contralateral amygdala and behavioral seizures were observed. These spontaneous seizures occurred in a pattern associated with stage 4 kindling, with rearing and bilateral forelimb clonus. Seizures persisted during the 30 days of the experiment. Recording from chronically implanted depth electrodes showed development of spike discharges, with recurrent seizures arising from amygdalar regions with propagation into both hippocampi. Aqueous iron is known to initiate lipid peroxidation by free radical mechanisms. Our observations suggest that epileptogenesis followed by chronic, spontaneous seizures could be initiated by deposition of iron-containing compounds into limbic structures of the rat.