Nicotine enhances cerebral glucose utilization in central components of the rat visual system

The effect of nicotine in visual system components of the rat brain was examined using the 2-deoxy-D-[1-14C]-glucose ([14C]DG) technique. Nicotine was administered subcutaneously (SC) at doses of 0.1, 0.3, and 1.0 mg/kg 2 min before the infusion of the radiotracer. Local cerebral glucose utilization (LCGU) was stimulated by nicotine in a dose-dependent manner in many brain regions associated with the visual system. Increases of over 100% were seen in the superior colliculus, nucleus of the optic tract, and portions of the accessory optic system (medial and dorsal terminal nuclei, and the inferior fasciculus). Statistically significant increases were also observed in the lateral geniculate nucleus, the lateral terminal nucleus and the cerebellum. The effects were blocked by pretreatment with mecamylamine and by enucleation. The findings lend support to the involvement of the nicotinic cholinergic system in the processing of visual information or visual-motor function.