Effects of cytochalasin B on Na+ content and cell volume of Entamoeba histolytica.
Cells of Entamoeba histolytica accumulated K+ and extruded Na+ compared to the concentrations of those ions present in the growth medium. Pinocytic activity, measured by the uptake of horseradish peroxidase of 125I-polyvinylpyrrolidone, was high (up to 0.3 ml/ml cells per h). Upon addition of cytochalasin B, at a concentration (20 microM) that completely blocked pinocytosis, cells lost up to 40% of their Na+ content within 90 min; K+ content was not affected or increased slightly compared to control cells without the inhibitor. Cation loss was associated with cell shrinkage. The dose-response curves for the effects of cytochalasin B on pinocytosis and Na+ content were identical. These data provide direct evidence that pinocytosis is an important component of the homeostatic system for Na+.
Bakker-Grunwald
T
T
Löhden
U
U
Trissl
D
D
D000818:Animals; D003571:Cytochalasin B / Q000494:pharmacology*; D004705:Endocytosis / Q000187:drug effects; D004748:Entamoeba histolytica / Q000166:cytology / Q000187:drug effects*; D010873:Pinocytosis / Q000187:drug effects; D012964:Sodium / Q000378:metabolism*; D014882:Water-Electrolyte Balance / Q000187:drug effects*
D003571:Cytochalasin B; D012964:Sodium