Which agent is a depolarizing ganglionic nicotinic agonist?

Which agent is a depolarizing ganglionic nicotinic agonist?

• A. Nicotine
• B. Mecamylamine
• C. Hexamethonium
• D. Scopolamine

Answer: (A)

Autonomic ganglionic transmission uses nicotinic acetylcholine receptors that are ligand-gated ion channels. A depolarizing nicotinic agonist binds and opens the channel, causing an initial influx of ions and depolarization, followed by receptor desensitization that reduces transmission. Nicotine is the classic compound that acts this way at autonomic ganglia, making it a depolarizing ganglionic nicotinic agonist. The other agents either block the receptor without causing depolarization (nicotinic antagonists) or affect muscarinic receptors rather than nicotinic ones, so they do not fit the depolarizing agonist profile.

Autonomic ganglionic transmission uses nicotinic acetylcholine receptors that are ligand-gated ion channels. A depolarizing nicotinic agonist binds and opens the channel, causing an initial influx of ions and depolarization, followed by receptor desensitization that reduces transmission. Nicotine is the classic compound that acts this way at autonomic ganglia, making it a depolarizing ganglionic nicotinic agonist. The other agents either block the receptor without causing depolarization (nicotinic antagonists) or affect muscarinic receptors rather than nicotinic ones, so they do not fit the depolarizing agonist profile.