text: UNLABELLED: Apparent muscarinic acetylcholine (mAch) receptor occupancy in mouse cerebral cortex, hippocampus, and striatum by scopolamine, an antagonist, and << biperiden >>, a relatively selective [[ M1 ]] antagonist, was estimated with competitive binding studies using two different radioligands: 3H-N-methyl piperidyl benzilate (3H-NMPB) and 3H-quinuclidinyl benzilate (3H-QNB).