Water and electrolyte balance in protoscoleces of Echinococcus granulosus incubated in vitro: effect of metabolic inhibitors.

REISIN IL; RABITO CA; CANTIELLO HF

INTERNATIONAL JOURNAL FOR PARASITOLOGY

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 1981

0020-7519

Water and electrolyte balance in protoscoleces of Echinococcus granulosus incubated in vitro: effect of metabolic inhibitors. International Journal for Parasitology 11: 405?410. The effects of metabolic inhibitors on the Na+, K+, Cl− and water balance of protoscoleces of Echinococcus granulosus (sheep strain) were studied in vitro. The protoscoleces were incubated at 37°C in Ringer Krebs solution for 3 h in the presence of iodoacetate, 3 mM (IA); potassium cyanide, 3 mm (KCN); 2−4 dinitrophenol, 0.2 mm (DNP); ouabain, 10−M or ethacrynic acid 0.5 mm. The effects of IA and/or KCN on the water and electrolyte balance were tested at high (0.95 × 105Pa) and low (0.05 × 105 Pa) oxygen tensions. Inhibitors produced a decrease in K+ as well as an increase in Na+ contents. At both high and low O2 tensions the Na+ balance was greatly altered by IA, the action of which could be already observed during the first hour of treatment. The cations did not reach a steady state balance during 3 h of incubation. At high oxygen tension Na+ and K+ balance was also altered by KCN or DNP though their actions were not as marked as that of IA. Ouabain affected the Na+ and K+ contents that reached new steady state distribution between 1.5 and 3 h of treatment while water and electrolyte contents were not modified by ethacrynic acid. In all the experiments no changes in Cl− and water contents were observed. It is concluded that the energy required to maintain the Na−K balance mechanisms within protoscoleces is largely provided by the anaerobic glycolytic pathway and that the aerobic oxidative pathway contribution to the energy balance is only accessory.