Scanning microfluorimetric studies of anticholinergic drugs in Schistosoma mansoni

A microfluorimetric technique has been used to analyze fluorescence in specimens of Schistosoma mansoni labeled with a dansylated analog of acetylcholine. Anticholinergic drugs inhibit the fluorescent labeling of living specimens. The effectiveness of anticholinergic agents can be expressed as a fractional decrease in observed fluorescence of specimens, and several drugs have been compared in this context. Atropine, eserine, carbachol and mecamylamine block fluorescence only at high concentrations (10(-4)--10(-3) M) while trifluoperazine and hycanthone block strongly at lower concentrations (10(-5) M). The findings reported here suggest that the relative activity of anticholinergic drugs is different in schistosomes and vertebrates.