Histochemical characterization of esterases from three species of amphistomes

Esterase activity of Gigantocotyle explanatum, Ceylonocotyle scoliocoelium and Cotylophoron cotylophorum were localized histochemically in various regions associated with nutrition, viz, integument, pharynx, sucker and gastrodermis. The intensity of the reactions varied in the different regions of the same parasite and also from species to species. The distribution and relative activity of the esterases were investigated and the results reveal that the influence of inhibitors/activators on enzyme activity varied in the different regions. Based on the inhibitory effects it is inferred that carboxylesterases are distributed in the region of the integument, pharynx and gastrodermis, acetylesterases in the suckers and cholinesterase in the subtegumental cells and muscle of these three trematodes.