Nematode nicotinic acetylcholine receptor B-subtype (B-subtype nAChR)

The Nematode nicotinic acetylcholine receptor B-subtype (B-subtype nAChR) is a pharmacologically distinct class of ligand-gated ion channels located on the body wall muscle of parasitic nematodes, such as Ascaris suum and Oesophagostomum dentatum. It is primarily characterized by its high sensitivity to the agonist bephenium and the antagonist derquantel, which distinguishes it from the levamisole-sensitive (L-subtype) and nicotine-sensitive (N-subtype) receptors found in the same organisms. In electrophysiological studies, the B-subtype is identified as a large-conductance channel (approximately 45 pS) that mediates excitatory neuromuscular transmission. Activation of these receptors by cholinergic agonists like bephenium or tribendimidine leads to persistent depolarization of the muscle cell membrane, resulting in spastic paralysis and the eventual expulsion of the parasite from the host. Conversely, selective antagonists like derquantel induce flaccid paralysis by competitively blocking the receptor's response to endogenous acetylcholine. The B-subtype nAChR represents a critical therapeutic target for anthelmintic drugs, particularly for treating infections resistant to other cholinergic agents.

Other names

Bephenium-sensitive nicotinic acetylcholine receptorB-type nAChRG45 nAChR channelBephenium-sensitive receptor

Agonists cause spastic paralysis through persistent depolarization of muscle cells, while antagonists cause flaccid paralysis by blocking acetylcholine-mediated activation.