Effects of cytoskeletal and ion-channel agents on the protoscolex of Echinococcus granulosus sensu lato

Helminthiases remain a major global health burden, and limitations of current anthelmintic therapies highlight the need for new pharmacological targets. This study examined the effects of ion channel and cytoskeletal modulators on bovine lung protoscoleces (PSCs) of Echinococcus granulosus sensu lato. Compounds acting on ion channels (praziquantel, amiloride, and amlodipine) and cytoskeletal components (albendazole and cytochalasin D) were evaluated using a semi-automated motility assay, methylene blue exclusion to assess viability, and scanning electron microscopy (SEM) to characterize structural damage. All compounds produced concentration-dependent reductions in motility. Amlodipine was the most potent inhibitor of motility, whereas praziquantel and cytochalasin D produced pronounced tegumental alterations. Amiloride was the least potent compound at both endpoints and produced the mildest ultrastructural lesions. In all cases, motility was nearly abolished at concentrations well below those required to reduce viability. After accounting for their shared concentration dependence, no statistically supported association remained, indicating that paralysis and loss of viability are largely distinct responses. No compound showed consistent recovery of motility within 24 h after washout. SEM analysis revealed extensive tegumental collapse, surface erosion, and microtrichial loss in PSCs exposed to cytoskeletal and calcium-modulating agents. These findings point to cytoskeletal organization and calcium-dependent ion fluxes as candidate vulnerabilities of the E. granulosus protoscolex.