Seizures in rats treated with kainic acid induce Fos-like immunoreactivity in locus coeruleus.

Kainic acid-triggered seizures (KATS) induce Fos-like immunoreactivity (FLI) in limbic structures, which send efferents to the locus coeruleus (LC). Following KATS, brain stem sections were stained for Fos immunocytochemistry and double immunostained for Fos and dopamine beta-hydroxylase (DBH). KA-treated animals showed significantly greater numbers of FLI neurons in the LC than control animals (p < 0.05). Co-localization of DBH/Fos was observed in 89.7% of the LC neurons in KA-treated animals and in 1.4% of LC neurons in control animals. Thus, KATS heavily induce Fos in DBH-containing neurons in the LC, which are known to project to the hippocampus. However, the role of activation of the LC noradrenergic neurons during KATS is not well understood at this present time.