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).