Sixteen dogs were anesthetized with pentobarbital sodium and placed on positive pressure ventilation. Twelve animals were cardiac paced and four animals were non-paced controls. In four of the paced animals, the left cut peripheral end of the cervical vagus was stimulated electrically. In another four animals, the decentralized left stellate ganglion was stimulated efferently. The four remaining paced animals were controls. The animals were injected i.v. with a single bolus of [14C]2-deoxyglucose, 100 microCi/kg. After 45 minutes of periodic stimulation, the hearts were removed, sectioned and prepared for autoradiography. Cardiac pacing significantly (p less than 0.02) decreased systolic blood pressure, and significantly increased (p less than 0.05) glucose utilization by all regions of the heart, with the exception of the left ventricular endocardium and the left ventricular papillary muscles. Vagal efferent stimulation elicited significant (p less than 0.05) decreases in glucose utilization in both the right atrium and right ventricle. Conversely, efferent stellate ganglion stimulation had no effect on the glucose utilization of any regions of the myocardium studied. This study demonstrates that both cardiac pacing and cardiac vagal efferent neuronal stimulation can produce distinct changes in regional myocardial glucose utilization.