Bethanechol receptor selectivity?

Bethanechol receptor selectivity?

• A. Non-selective at cholinergic receptors
• B. Selective for muscarinic receptor
• C. Selective for nicotinic receptor
• D. Antagonist at muscarinic receptor

Answer: (B)

Bethanechol acts as a direct-acting cholinergic agonist with a strong preference for muscarinic receptors. Its structure as a quaternary ammonium compound makes it mainly affect muscarinic sites (the parasympathetic targets in smooth muscle and glands) and greatly limits activity at nicotinic receptors at autonomic ganglia and the NMJ. Because of this selectivity, it promotes parasympathetic actions like increased GI motility and bladder contraction without activating nicotinic receptors, and it is not an antagonist. This is why the best description is that it is selective for muscarinic receptors.

Bethanechol acts as a direct-acting cholinergic agonist with a strong preference for muscarinic receptors. Its structure as a quaternary ammonium compound makes it mainly affect muscarinic sites (the parasympathetic targets in smooth muscle and glands) and greatly limits activity at nicotinic receptors at autonomic ganglia and the NMJ. Because of this selectivity, it promotes parasympathetic actions like increased GI motility and bladder contraction without activating nicotinic receptors, and it is not an antagonist. This is why the best description is that it is selective for muscarinic receptors.