Extracellular single-unit recordings were made from noradrenergic locus coeruleus neurons in chloral hydrate-anesthetized male Sprague-Dawley rats. Acute intravenous administration of the antidepressant trazodone produced a mild excitation of firing of these cells (ED25 = 0.128 mg/kg; ED50 = 0.659 mg/kg). These findings, in combination with previous work showing that trazodone inhibits the firing of serotonergic dorsal raphe neurons indicate that trazodone modulates monoaminergic neuronal activity in the brain and suggest a unique electrophysiological profile for this drug among antidepressants.