Cholinergic Receptors

Cell surface receptors known as cholinergic receptors are activated upon binding the neurotransmitter acetylcholine. Cholinergic receptors are divided into nicotinic and muscarinic receptors, named after the medications that act on them. Nicotinic acetylcholine receptors, or nAChRs for short, are highly responsive to nicotine. They are also referred to as “ionotropic” cholinergic receptors. Muscarinic acetylcholine receptors (mAChR, also called “metabotropic” acetylcholine receptors) are incredibly receptive to muscarine. The nicotine ACh receptor is also a Na⁺, K⁺, and Ca²⁺ion channel. Curare, hexamethonium, and toxins found in the venom of snakes and shellfish, such as bungarotoxin, can all block nicotinic acetylcholine receptors. Medications like neuromuscular blocking drugs, frequently used in anesthesia, bind reversibly to the nicotinic receptors in the neuromuscular junction. The primary mechanism through which nicotine’s effects are mediated is by nicotinic receptors....