RT Book, Section A1 Panus, Peter C. A1 Jobst, Erin E. A1 Masters, Susan B. A1 Katzung, Bertram A1 Tinsley, Suzanne L. A1 Trevor, Anthony J. SR Print(0) ID 6090455 T1 Chapter 5. Drugs Affecting the Cholinergic System T2 Pharmacology for the Physical Therapist YR 2009 FD 2009 PB The McGraw-Hill Companies PP New York, NY SN 978-0-07-146043-9 LK accessphysiotherapy.mhmedical.com/content.aspx?aid=6090455 RD 2024/11/07 AB When synaptic transmission depends upon acetylcholine as the primary neurotransmitter, it is labeled cholinergic. The termination of acetylcholine activity is mediated by the enzymeacetylcholinesterase. There are two subtypes of cholinergic receptors, muscarinic (M) and nicotinic (N). Agonists that mimic the effects of acetylcholine are defined as cholinomimetics. Some drugs are direct-acting agonists for the cholinergic receptors (Figure 5–1). Other drugs function as indirect-acting agonists by preventing the inactivation of acetylcholine. Antagonists that inhibit acetylcholine at muscarinic or nicotinic receptors are defined as anticholinergics. Drugs that selectively inhibit muscarinic receptors are called antimuscarinics (Figure 5–2), whereas those that selectively inhibit nicotinic receptors are antinicotinics.