The use of bispyridinium non-oxime analogues for the restoration of nerve agent impaired neuromuscular transmission in rat hemidiaphragms – Structure optimization

• Published in: Toxicology letters Vol. 397; pp. 42 - 47
• Main Authors: Amend, Niko, Timperley, Christopher M., Bird, Mike, Green, A.Christopher, Worek, Franz, Seeger, Thomas
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-06-2024
• Subjects: Acetylcholinesterase; Bispyridinium non-oximes; Nerve agent; Nicotinic receptor; Organophosphate; Bispyridinium non-oximes; Organophosphate; Acetylcholinesterase; Nerve agent; Nicotinic receptor
• ISSN: 0378-4274; 1879-3169; 1879-3169
• DOI: 10.1016/j.toxlet.2024.04.015

Organophosphate pesticide poisoning challenges health care systems worldwide. Furthermore, nerve agents remain a continuous threat. The treatment options for organophosphate poisoning have virtually been unchanged for decades, relying on symptomatic treatment and the use of oximes to indirectly restore neuromuscular function. Hence, compounds targeting directly nicotinic acetylcholine receptors (nAChRs) might substantially improve treatment options. The current study investigated a series of bispyridinium analogues with a trimethylene or 2,2′-diethyloxy linker in a rat hemidiaphragm model, using indirect field stimulation. Methyl- and ethyl-substituted bispyridinium analogues restored neuromuscular function up to 37 ± 17% (MB419, a 3-methyl analogue) at a stimulation frequency of 20 Hz. The bispyridinium analogues with a 2- or 3-methyl group, or a 2- or 3-ethyl group, tended towards a higher restoration of neuromuscular function than those with a 4-methyl or 4-ethyl group, respectively. The current data can be used for future studies to optimize structure-based molecular modeling of compounds targeting the nAChR.
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•Bispyridinium non-oximes analogues with a trimethylene or 2,2′-diethyloxy linker and various substituents were studied.•Methyl- and ethyl- substituted compounds with a trimethylene linker were able to partially restore muscle force.•The investigated bispyridinium analogues can be used for future studies to optimize structure-based molecular modeling.