Effect of phenothiazines on Hymenolepis diminuta with special reference to the brush border Ca2+-dependent ATPase.
Incubation of Hymenolepis diminuta with the calmodulin antagonist trifluoperazine causes lesions in the brush border of the cestode. Exposure to a phenothiazine of lower lipophilicity, trifluoperazine sulphoxide, had little effect. Characterisation of isolated brush border revealed two forms of Ca2+-ATPase which exhibited maximum activity at pH 5.5 and 7.5. Both forms were Ca2+-dependent but only the latter was influenced by calmodulin and trifluoperazine. It is suggested that the Ca2+-ATPase present in the tapeworm brush border may be the site of trifluoperazine toxicity.
D000818:Animals; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002147:Calmodulin / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D006926:Hymenolepis / Q000187:drug effects* / Q000201:enzymology / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D008871:Microvilli / Q000187:drug effects / Q000201:enzymology / Q000648:ultrastructure; D014268:Trifluoperazine / Q000031:analogs & derivatives / Q000494:pharmacology*
D002147:Calmodulin; C039697:trifluoperazine sulfoxide; D014268:Trifluoperazine; D000252:Calcium-Transporting ATPases