Transection of the pineal stalk produces convulsions in male Mongolian gerbils (Meriones unguiculatus).

The pineal gland has been implicated in the regulation of epileptic-like seizures in gerbils. Pinealectomy of gerbils results in seizures which affect approximately 80% of the gerbils. Telencephalic catecholamine levels are depressed by pinealectomy in gerbils and it has been suggested that the reduced norepinephrine (NE) levels are responsible for initiating or facilitating these seizures. The present study found that pineal stalk transection produced convulsions in gerbils which were indistinguishable from pinealectomy-induced convulsions. Stalk transection also produced a depression (38%) in parietal cortex NE levels which was similar to a depression observed in pinealectomized gerbils (52%). These depressions in cortical NE levels were not observed in other brain regions, specifically the hippocampus or the amygdala. However, a decline (25%) in hypothalamic NE levels was observed after stalk transection. These results suggest that the signals responsible for pinealectomy-induced convulsions are carried by the pineal stalk and that pinealectomy produces regional, not global, reductions in NE content.