title: Involvement of contractile protein in hypotonic expansion of macrophages.
abstract: The volume measurement of macrophages from rabbit lungs was carried out using an automatic computerized cell counter. The size of freshly prepared macrophages was 669 +/- 62 fl at 4 degrees C. The cell volume increased gradually when the cells were suspended in an isotonic saline solution. Cytochalasin B initially enhanced the increase in cell volume but then caused a reduction. The reduction was considered to be due to structural changes in filament network of contractile proteins. Under hypotonic conditions, cytochalasin B-treated cells showed increased osmotic fragility and reduced expansibility. The increased fragility was considered to result from impairment of the network structure. These findings of the effect of cytochalasin B on the volume change suggest that contractile proteins play a protective role in the membrane against hypotonic expansion.
mesh_terms: D000818:Animals; D003285:Contractile Proteins / Q000502:physiology*; D003571:Cytochalasin B / Q000494:pharmacology; D066298:In Vitro Techniques; D008264:Macrophages / Q000166:cytology* / Q000187:drug effects; D009994:Osmolar Concentration; D009996:Osmotic Fragility / Q000187:drug effects; D010042:Ouabain / Q000494:pharmacology; D011817:Rabbits; D013696:Temperature
chemical_list: D003285:Contractile Proteins; D003571:Cytochalasin B; D010042:Ouabain