(colour online) Expression of different parasite nAChRs using Xenopus oocyte expression reveals the effect of subunit combinations on anthelmintic sensitivity. Antagonism of derquantel depends on nAChR subtype, demonstrated using two of the four different expressed O. dentatum subunits that can occur. (A) Expression of Ode-UNC-63:Ode-UNC-29:Ode-UNC-38:Ode-ACR-8 in Xenopus oocytes produces receptors that, under voltage clamp, produce currents to acetylcholine, levamisole, tribendimidine, pyrantel, bephenium, thenium and nicotine, with the biggest current to levamisole. This receptor is competitively antagonized by derquantel (plot). (B) Expression of Ode-UNC-63:Ode-UNC-29:Ode-UNC-38 in Xenopus oocytes produces receptors that, under voltage clamp, produce currents to acetylcholine, levamisole, tribendimidine, pyrantel, bephenium, thenium and nicotine, with the biggest current to pyrantel. This receptor is non-competitively antagonized by derquantel (plot).