Effect of stimulation of the nucleus basalis of Meynert on blood flow and extracellular lactate in the cerebral cortex with special reference to the effect of noxious stimulation of skin and hypoxia

Cerebral blood flow (CBF) and extracellular lactate in the parietal cortex were simultaneously measured in halothane-anesthetized rats. Focal electrical stimulation of the magnocellular nucleus of the basal forebrain (nucleus basalis of Meynert; NBM) for 10 min produced a significant increase in cortical CBF without any significant changes in extracellular lactate in the parietal cortex or in systemic arterial blood pressure (BP). Cutaneous pinching of a hindpaw for 10 min increased cortical CBF and BP, but did not influence extracellular cortical lactate. Systemic hypoxia for 10 min reducing the end-tidal O 2 concentration from 18% to 6–8% produced a remarkable increase in extracellular cortical lactate. It was suggested that the increased cortical CBF following either NBM stimulation or pinching of a hindpaw was not due to metabolic changes in the cortical neurons of anesthetized rats.