GLUCOSE ATTENUATES THE EFFECT OF COMBINED MUSCARINIC-NICOTINIC RECEPTOR BLOCKADE ON SPONTANEOUS-ALTERNATION

Glucose administration reverses the effects of both muscarinic and nic otinic cholinergic receptor antagonists on memory and other measures. In experiment 1, we found that glucose attenuated impairments on spont aneous alternation after muscarinic (scopolamine, 0.5 mg/kg) or nicoti nic (mecamylamine, 5.0 mg/kg) receptor blockade. In experiment 2, we e xamined whether glucose could reverse the spontaneous alternation impa irments produced by combined muscarinic-nicotinic receptor blockade. S copolamine (0.1 mg/kg) and mecamylamine (2.5 mg/kg) when administered separately did not modify alternation performance, but when coadminist ered they decreased spontaneous alternation scores. This decrease was attenuated by glucose at 100, 300, 500 and 3000 mg/kg. These findings suggest that glucose may attenuate the behavioral impairment by enhanc ing cholinergic activity and/or other neurotransmitter systems.