Amygdaloid kindling elicits persistent changes in pertussis toxin-catalyzed ADP-ribosylation

We examined the changes in pertussis toxin (PTX)-catalyzed ADP-ribosylation in amygdaloid-kindled rats to clarify the role of G proteins in the basic mechanisms of epilepsies. Autoradiographic analysis showed a remarkable increase in PTX-catalyzed ADP-ribosylation in 39-41-kDa proteins in hippocampus and cerebral cortex of kindled animals. The 39- to 41-kDa proteins were shown to be alpha-subunits of Gi and Go by immunoblotting with specific anti-Gi alpha and anti-Go alpha. The increase in ADP-ribosylation of these proteins was observed on stimulated and unstimulated sides of brains 24 h after the last generalized seizure and persisted for at least 3-4 weeks. These results suggest that persistent alterations in signal transduction through Gi and Go might be related to acquisition of long-lasting epileptogenesis.