Anticholinergic antiparkinson agents or acetylcholine antagonists block the muscarinic acetylcholine receptors and cholinergic nerve activity. Activation of muscarinic receptors has an excitatory effect, opposite to that of dopaminergic activation, so suppression of the effects of acetylcholine compensates for a lack of dopamine in Parkinson's disease. Acetylcholine and dopamine have to be carefully balanced for proper body movement. Anticholinergic agents create a better balance between acetylcholine and dopamine. Anticholinergic agents are used to treat patients with Parkinson's disease who have tremor.