Sustained increase in Narp protein expression following repeated electroconvulsive seizure.

The delayed response to many psychiatric treatment regimens has focused attention on identifying enduring changes in gene expression following repeated stimulation that may contribute to these responses. Recent studies have identified Narp protein as a neuronal immediate early gene product that remains elevated in the hippocampus nearly 24 hours after a single episode of electroconvulsive seizure (ECS). To examine how Narp expression responds to repeated stimulation, we have examined the effect of repeated ECS on Narp expression in the hippocampus. We report that Narp protein levels remain elevated, about six-fold higher than basal levels, at 48 hours after the last of a series of five or six ECS given every other day. As Narp protein appears to play a key role in regulating AMPA receptor clustering at synaptic sites, sustained increases in Narp may contribute to changes in excitatory synaptic transmission induced by chronic neuronal stimulation.