Rat corticotropin-releasing factor (CRF) microinfused unilaterally or bilaterally into the locus coeruleus (LC) of awake, chronically cannulated rats produced a dose-dependent ECoG desynchronization and behavioral activation. ECoG spectra analysis revealed a significant decrease of total voltage power and of 0.25-3 and 3-6 Hz frequency bands. These effects were prevented by a pretreatment into the same site with alpha-hCRF, a selective antagonist at CRF receptors and by alprazolam, a benzodiazepine derivative. In conclusion, the present results indicate that CRF produces its behavioral and ECoG activating effects by interaction with specific receptors located on LC neurons.