premise: Muscarinic acetylcholine receptors are actylcholine receptors.
hypothesis: Muscarinic acetylcholine receptors , or mAChRs , are acetylcholine receptors that form G protein-receptor complexes in the cell membranes of certain neurons and other cells . Muscarinic antagonist . Acetylcholine ( often abbreviated ACh ) is a neurotransmitter whose receptor is a protein found in synapses and other cell membranes .