The anthelmintic pyrantel acts as a low efficacious agonist and an open-channel blocker of mammalian acetylcholine receptors.

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Rayes D, De Rosa MJ, Spitzmaul G, Bouzat C

The anthelmintic pyrantel acts as a low efficacious agonist and an open-channel blocker of mammalian acetylcholine receptors.

Neuropharmacology. 2001 Aug;41(2):238-45.

PubMed ID

11489460 [ View in PubMed

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Abstract

Pyrantel is an anthelmintic which acts as an agonist of nicotinic receptors (AChRs) of nematodes and exerts its therapeutic effects by depolarizing their muscle membranes. Here we explore at the single-channel level the action of pyrantel at mammalian muscle AChR. AChR currents are elicited by pyrantel. However, openings do not appear in clearly identifiable clusters over a range of pyrantel concentrations (1-300 microM). The mean open time decreases as a function of concentration, indicating an additional open-channel block. Single-channel recordings in the presence of high ACh concentrations and pyrantel demonstrate that the anthelmintic acts as a high-affinity open-channel blocker. When analyzed in terms of a sequential blocking scheme, the calculated forward rate constant for the blocking process is 8x10(7) M(-1) x s(-1), the apparent dissociation constant is 8 microM at a membrane potential of -70 mV and the process is voltage dependent. Pyrantel displaces alpha-bungarotoxin binding but the concentration dependence of equilibrium binding is shifted towards higher concentrations with respect to that of ACh binding. Thus, by acting at the binding site pyrantel activates mammalian AChRs with low efficacy, and by sterical blockade of the pore, the activated channels are then rapidly inhibited.

DrugBank Data that Cites this Article

Drugs

Pyrantel

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Pyrantel	Muscarinic acetylcholine receptor M1	Protein	Humans	No	Antagonist Agonist	Details