Quantitative studies on acetylcholinesterase in seven species of digenetic trematodes.

Quantitative estimation of absolute levels and in vitro release of acetylcholinesterase (AChE) in seven species of digenetic trematodes: Isoparorchis hypselobagri from the swim bladder of catfish, Wallago attu; Srivastavaia indica and Gastrothylax crumenifer from the rumen, and Gigantocotyle explanatum from the liver of the water buffalo, Bubalus bubalis; Fasciolopsis buski, Echinostoma malayanum from the small intestine and Gastrodiscoides hominis from the caecum of the pig, Sus scrofa revealed that the enzyme is present in remarkably high quantities in species which inhibit gastrointestinal tract compared with those that parasitize liver and swim bladder. The rate of in vitro release of AChE also varies with the species which supports the view that such differential secretion probably takes place in situ as well to counteract peristalsis and it is a biochemical adaptation on the part of these trematodes.