Brain content of immunoreactive [Leu5]enkephalin and [Met5]enkephalin after pentylenetetrazol-induced convulsions.

Wistar rats were injected daily with convulsant doses of PTZ (40 mg/kg). The brain content of immunoreactive (IR) enkephalins was measured after repetitive clonic convulsions and after the 'kindling' state was reached. In both instances we found a significant increase of IR [Leu5]enkephalin and IR [Met5]enkephalin in septum, striatum and amygdala 24 h after PTZ administration. These results support the suggestion that the peptide increase occurs with repetitive convulsions and not only after the 'kindling' state is reached.