Effects of hycanthone on neuromuscular systems of Schistoma mansoni

Hycanthone has a variety of effects on muscular activity and neurotransmitter systems of schistosomes. These include interference with neuronal storage of 5-hydroxytryptamine (5-HT), an increase in the length of schistosomes, a weak stimulation of motor activity, and an inhibition of acetylcholinesterase activity. However, the findings reported in this paper indicate that none of these effects can be related to the mode of the antischistosomal action of hycanthone because (a) these effects are observable only after, but not prior to, the hepatic shift, (b) they are not demonstrable with anti-schistosomal strucutral analogs of hycanthone, or (c) the same effects are elicited in hycanthone-resistant schistosomes. Dansyl choline, under conditions recommended by others, does not stain selectively neuronal structures of schistosomes, but such structures can be visualized under different conditions. However, this stain lacks specificity for cholinergic neurons or receptors because no cholinergic drug can block binding of dansyl choline and because the same fluorescence staining effects are observed with dansic acid and dansyl chloride.