Calmodulin levels were measured in different areas of brain in rats rendered physically dependent and after single doses (6 g/kg) of ethanol. After single doses of ethanol no changes in the calmodulin levels were found in the cortex, but those in the hippocampus and caudate nuclei were increased while those in the cerebellum were reduced. In the dependent intoxicated (prodromal) rats, calmodulin levels were elevated in all these regions except the cerebellum. In rats undergoing ethanol withdrawal syndrome, the calmodulin levels decreased in all regions of the brain except caudate nuclei.