Effects of acute administration of caffeine on local cerebral glucose utilization in the rat.

The quantitative 2-[14C]deoxyglucose autoradiographic method was used to study the effects of acute intravenous injections (15 min prior to study) of caffeine on brain energy metabolism. With doses of 0.1 mg/kg the effects of caffeine on cerebral glucose utilization were limited to the habenula, spinal trigeminal and paraventricular nuclei. After the 1.0 mg/kg dose significant increases were additionally seen in the caudate, ventral tegmental area and medial septum. After the injection of 10 mg/kg of caffeine, average glucose utilization of the brain as a whole was increased by 15%, and of 71 structures examined 31 structures were statistically significantly affected. Among these were all brainstem monoaminergic cell groupings, components of the extrapyramidal motor system, anterior cingulate, and medial prefrontal cortex. In the hypothalamus glucose utilization increased only in the paraventricular nucleus, arcuate nucleus, and median eminence. This study demonstrates that there is a correlation between the known stimulant effects of caffeine on behavior and widespread increases in glucose utilization throughout the brain.