The mode of action of some benzimidazole drugs onTrichinella spiralis

Abstract

SUMMARYIn an attempt to find possible targets for benzimidazole action in muscle-stage larvae ofTrichinella spiralis, the effects of mebendazole and thiabendazole were testedin vivoby oral treatment of infested mice andin vitroby including these anthelmintics in an adequate maintenance medium containing decapsulated larvae. The effects of the anthelmintics on succinate dehydrogenase and fumarate reductase activities, measured in the mitochondrial fraction obtained from thein vivo- orin vitro-treated larvae showed that only thiabendazole causes significant inhibition of fumarate reductase activity. On the other hand, measurements of free glucose, glycogen reserves and soluble protein in the treated larvae indicate thatin vivo, mebendazole and thiabendazole clearly diminish free glucose levels, althoughin vitroonly mebendazole produces the same diminution. Both the glycogen and protein contents of the larvae remained unchanged after treatmentin vivoorin vitro.The importance of these findings with regard to a possible site of action for mebendazole and thiabendazole is discussed.