Interaction of ivermectin with γ-aminobutyric acid receptors in Trichinella spiralis muscle larvae

17 February 1999

journal article
Published by Springer Nature in Zeitschrift Fur Parasitenkunde-Parasitology Research

Vol. 85 (4) , 320-323
https://doi.org/10.1007/s004360050555

Abstract

The value of the γ-aminobutyric acid (GABA) receptor of nematodes as a target for ivermectin's mode of action remains unclear. Using binding assays, we examined extracts from Trichinella spiralis muscle larvae for the presence of [³H]-ivermectin and [³H]-GABA binding sites. Tissue preparations displayed affinity binding sites for [³H]-ivermectin with a dissociation constant (K _d) of 83 nM and a receptor density (B_max) of 145 fmol/mg protein. We also identified a specific [³H]-GABA binding activity with a K _d of 1.2 μM and a B_maxof 4.78 pmol/mg protein. In competition studies, ivermectin was found to be a competitive inhibitor of specific [³H]-GABA binding activity with an inhibition constant (K _i) of 3.39 nM, suggesting that GABA receptors could be implicated in the mechanism of action of ivermectin in nematodes.

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