Published online by Cambridge University Press: 06 April 2009
The adenine nucleotide content and adenylate energy charge of Nematospiroides dubius from laboratory mice and of Trichostrongylus colubriformis from lambs has been measured. Administration of the anthelmintic, levamisole, to infected hosts resulted in only a slight fall in the adenylate energy charge of N. dubius over a 3-h period but there was a greater fall in the adenylate energy charge of T. colubriformis during this period. In neither case did the energy charge fall quickly, nor did it fall to the low levels which would be expected if the levamisole were inhibiting synthesis of ATP. The changes in energy charge of the nematodes which occurred following administration of levamisole to their hosts was of the order which can be satisfactorily explained by changes in the environment of the nematodes, such as reduced oxygen tension. It is concluded that the maintenance of levamisole-induced paralysis of these two species of trichostrongyle in vivo does not rely on the inhibition of fumarate reductase.