Nematode muscle nicotinic acetylcholine receptor (nAChR) (nAChR)

Nematode muscle nicotinic acetylcholine receptors (nAChRs) are essential pentameric ligand-gated ion channels located at the neuromuscular junctions of parasitic and free-living roundworms (Martin et al., 2012; PubMed: 22403568). These receptors mediate excitatory neurotransmission by opening a cation-conducting pore upon binding acetylcholine, which triggers muscle depolarization and contraction necessary for locomotion and feeding (Richmond & Jorgensen, 1999; PubMed: 10518497). They are categorized into distinct subtypes based on their pharmacological sensitivity, most notably the levamisole-sensitive (L-type) and nicotine-sensitive (N-type) receptors (Robertson et al., 2002; PubMed: 12167204). Because these receptors are critical for the parasite's ability to maintain its position within the host, they serve as primary targets for several classes of anthelmintic drugs. Agonists like levamisole and pyrantel cause overstimulation and spastic paralysis, while antagonists like derquantel induce flaccid paralysis, both leading to the expulsion or death of the nematode (Kopp et al., 2008; PubMed: 18616766). The high degree of structural divergence between nematode and mammalian muscle nAChRs provides the molecular basis for the selective toxicity required for clinical safety (Harrow & Gration, 1985; PubMed: 4033331). Resistance to these drugs often arises through mutations in the genes encoding specific receptor subunits, such as unc-38 or unc-29, which reduces drug binding or channel function (Lewis et al., 1980; PubMed: 7400241). Understanding the diversity of these receptors across different nematode species is crucial for developing next-generation anthelmintics that can overcome existing resistance patterns.

Other names

Levamisole-sensitive nicotinic acetylcholine receptorL-nAChRNicotine-sensitive nicotinic acetylcholine receptorN-nAChRMuscle-type nicotinic receptorSomatic muscle nAChR

Agonist-induced spastic paralysis or antagonist-induced flaccid paralysis of nematode somatic muscles through the modulation of cation-selective ion channels.