ALTERATION OF CAM-I MESSENGER-RNA EXPRESSION IN THE DEVELOPING RAT SUPERIOR COLLICULUS FOLLOWING CHRONIC TREATMENT WITH AN NMDA RECEPTOR ANTAGONIST

The spatial distribution of CaM I mRNA was investigated in the develop ing superior colliculus of rats that were chronically treated with the NMDA receptor antagonist AP-5. In control animals, CaM I message was localized in a continuous band of cells that extended across the entir e rostro caudal axis of the superficial superior colliculus. Chronic A P-5 treatment resulted in a specific reduction of CaM I message in the caudal colliculus at postnatal day 10. Since normal NMDA receptor fun ction has been implicated in activity dependent synaptic plasticity in the superior colliculus, these results suggest that the regulation of calmodulin may be part of a cascade of events that mediate this plast icity following NMDA receptor activation.