Abstract
Effects of lisuride, a central dopamine and serotonin agonist of the ergot type, on local cerebral glucose utilization were studied in conscious, anesthetized, and substantia nigra-lesioned rats using the autoradiographic 2-deoxyglucose method. In the conscious rat, lisuride produced dose-dependent (0.05-0.5 mg/kg s.c.) increases of glucose utilization in the cerebellar gray structures (lobule of culmen, vermian lobule, uvula, cerebellar hemisphere) and the lateral nucleus of the thalamus. Although some other gray structures including cerebral cortex were also slightly stimulated, no change was observed in the hippocampus, hypothalamus, amygdala, mammilary body, superior colliculus, pons, and any of the white structure. The stimulatory effect of lisuride was abolished almost completely by the pretreatment with sulpiride or haloperidol. Pentobarbital and γ-butyrolactone produced marked reduction in the glucose utilization all over the brain, and these effects were not affected by the pretreatment of lisuride. A unilateral 6-hydroxydopamine lesion at the substantia nigra caused a reduction of glucose utilization in the ipsilateral auditory cortex that was reversed by the administration of lisuride. These results indicate that lisuride modulates the motion coordination function of the cerebellum through the cerebral cortex.
