[Effect of stimulation of the locus coeruleus on cobalt-induced epileptiform activity in the rat]

The effects of a short-time serial stimulation of the locus coeruleus (LC) on cobalt-induced focal epileptiform activity were investigated in unrestrained rats with chronically implanted electrodes. The results show a marked reduction of the spike-wave activity immediately after stimulation. The characteristic groups of "cobalt-spikes" are completely suppressed within 30 s and significantly reduced up to 120 s. This suppression was partly antagonized by pretreatment with the beta-receptor antagonist propranolol (2-5 mg/kg i.p.). On the other hand, the stimulation of other areas, lateral or medial of the LC (n. parabrachialis; stratum griseum centrale), reduced the spike-discharges only insignificantly. These data support the hypothesis that the noradrenergic system play an important inhibitory role in epileptiform activity.