Glucose utilization in the Papez circuit: effects of oxotremorine and scopolamine

The [14C]2-deoxy-D-glucose technique was used to test the effects of central muscarinic stimulation or antagonism on local cerebral glucose utilization (LCGU) in the rat limbic system. Systemic administration of the muscarinic agonist oxotremorine (OXO, 0.05, 0.1 or 0.7 mg/kg, i.p.), increased LCGU in the pre- and postsubiculum, anterior nuclei of the thalamus, mammillary bodies, retrosplenial medial cortex, medial septum, postcommissural fornix and mammillothalamic tract. Scopolamine (2.5 mg/kg, i.p.) blocked these effects, and independently decreased LCGU in the pre- and postsubiculum, anterior thalamic nuclei, and retrosplenial medial cortex. The affected brain regions are components of, or are connected with, the Papez circuit.