Effects of the indirect dopaminomimetic diethylpemoline on local cerebral glucose utilization and local cerebral blood flow in the conscious rat.

The changes in local cerebral glucose utilization (LCGU) and local cerebral blood flow (LCBF) following the systemic application of the indirect dopaminomimetic diethylpemoline (50 mg/kg i.v.) were measured in conscious rats using the autoradiographic [14C]2-deoxyglucose and the [14C] iodoantipyrine technique. Increased rates of glucose utilization were observed in the sensorimotor cortex, parafascicular nucleus, ventrolateral nucleus of the thalamus, substantia nigra, caudate nucleus, globus pallidus, red nucleus, subthalamic nucleus, cerebellar cortex and vermis. Cingulate cortex, anteromedial, anteroventral nucleus of the thalamus, habenula and nucleus accumbens showed a decreased LCGU. The determination of LCBF revealed a similar pattern of altered blood flow values. Statistical evaluation of the relationship between glucose utilization and blood flow by regression analysis did not reveal any distinguishable difference between diethylpemoline-treated rats and controls. The data suggest that it is mainly the altered neuronal activity and metabolic demand after dopaminergic stimulation that effect the changes in blood flow rather than a direct dopaminergic effect on brain vasculature.