Changes in the level of acetylcholinesterase of nematospiroides dubius and Trichostrongylus colubriformis following paralysis by levamisole in vivo.

Acetylcholinesterase (acetylcholine acetylhydrolase; EC 3.1.1.7) levels of Nematospiroides dubius from laboratory mice and Trichostrongylus colubriformis from lambs have been measured. The anthelmintic levamisole (leavo isomer of 2,3,5,6-tetrahydro-6-phenylimidazo-(2,1b)-thiazole (Tetramizole)) did not affect the level of acetylcholinesterase in N. dubius in vivo but caused a reduction in the level of the enzyme in T. colubriformis following paralysis in vivo. The effect of levamisole on acetylcholinesterase in the nematodes is explained in terms of the differing roles of the enzyme in these two species.