Final answer:
The metabotropic receptor for acetylcholine is the muscarinic receptor, a G protein-coupled receptor known to also bind muscarine.
Step-by-step explanation:
The metabotropic receptor for acetylcholine is the muscarinic receptor. This type of acetylcholine receptor is distinguished by its ability to bind muscarine, a substance found in certain mushrooms, and is known to be a G protein-coupled receptor (metabotropic receptor). On the other hand, the nicotinic receptor is characterized by its ability to bind nicotine and is an ionotropic receptor. The cholinergic system comprises these two classes of receptors: the muscarinic and nicotinic receptors. Both types of receptors bind acetylcholine (ACh) and induce cellular responses, but they are highly specific and do not exhibit cross-reactivity with the molecule that isn't specific to them.