MK-801 INCREASES ENDOGENOUS ACETYLCHOLINE-RELEASE IN THE RAT PARIETAL CORTEX - A STUDY USING BRAIN MICRODIALYSIS

Glutaminergic and cholinergic neuronal interactions were investigated by using the brain microdialysis method in freely-moving rats. Acute administration of (+)-10,11-dihydro-5-methyl-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate (MK-801) increased dose-dependently the extracellular acetylcholine (ACh) level in the rat parietal cortex. Significant increases in the extracellular ACh level were observed at doses of 0.4 and 0.5 mg/kg of MK-801, compared with the saline-treated group. The increase of extracellular ACh level was eliminated by infusion of 10(-2) M N-methyl-D-aspartate (NMDA). These results suggest that the glutaminergic neuronal system regulates functions of the cholinergic neuronal system.