The olfactory bulb of adult male rats stimulated with propionic acid vapours displays a characteristic focus of high metabolic activity in the dorso-medial glomeruli, as revealed by the 2-deoxyglucose (2DG) method. Injection of the dopaminergic agonist apomorphine (1.5 mg kg-1) prior to odour stimulation completely abolishes this selective pattern of glomerular activation, while the metabolic activity of other bulbar areas is not significantly altered. This effect is abolished by a previous injection of the dopamine antagonist haloperidol (0.1 mg kg-1). These observations emphasize the probable involvement of dopamine and dopamine receptors in the bulbar processing of olfactory information.