Responses of cortical cerebral blood flow (CBF) in the parietal cortex following electrical stimulation of cervical sympathetic trunks (CSTs) were compared in healthy adult (4-6 months old) and healthy aged (28-32 months old) Fischer-344 rats anesthetized with urethane. The cortical CBF was continuously monitored using laser Doppler flowmetry (LDF). The electrical stimulation of CSTs with supramaximum intensity caused the frequency-dependent initial-increase and late-decrease responses of cortical CBF in both adult and aged rats. There were no significant differences in magnitude and time course of the responses of the cortical CBF with the comparable frequencies of the electrical stimulation of the CSTs between the adult and the aged rats. These evidences suggest that the neural control of the cortical CBF by the sympathetic nerves is quite well maintained in aged rats.