EFFECTS OF PHYSOSTIGMINE ON LOCAL CEREBRAL GLUCOSE-UTILIZATION IN THECENTRAL COMPONENTS OF THE RAT VISUAL-SYSTEM

The effects of intravenous administration of physostigmine at doses of 0.03, 0.095, or 0.3 mg/kg on local cerebral glucose utilization (LCGU ) were determined in 3 structures of the visual system of the rat brai n by means of the quantitative 2-[C-14]deoxyglucose method. LCGU was i ncreased in the superior colliculus (superficial gray layer), but unch anged in the visual cortex and the lateral geniculate body. To determi ne whether the observed effect of physostigmine on the superior collic ulus depended on input from the retina, the highest dose of physostigm ine was administered to rats which had previously been enucleated bila terally. Enucleation decreased LCGU in the superior colliculus of the animals not treated with physostigmine and blocked the effect of physo stigmine on LCGU. The effect of physostigmine in the superior collicul us appears, therefore, to depend on input from the retina.