Final answer:
Muscarinic cholinergic drugs primarily affect muscarinic receptors at certain doses. These drugs can be muscarinic agonists or antagonists that enhance or inhibit cholinergic effects, respectively.
Step-by-step explanation:
The cholinergic system includes two classes of receptor: the nicotinic receptor and the muscarinic receptor. Both receptor types bind to acetylcholine (ACh) and cause changes in the target cell. The nicotinic receptor is a ligand-gated cation channel and the muscarinic receptor is a G protein-coupled receptor.
Cholinergic drugs that primarily affect muscarinic receptors will have their effects at certain doses. These drugs are muscarinic agonists or antagonists that can enhance or inhibit cholinergic effects, respectively.
For example, muscarinic agonists like pilocarpine can activate muscarinic receptors and cause various physiological responses, while muscarinic antagonists like atropine can block the effects of acetylcholine at muscarinic receptors.