Cytochalasin B partially inhibits the oxalate-induced radial segmentation of mononucleated blood cells.

Cytochalasin B (CB), 5 microgram/ml (= 1.0 x 10(-5) M), inhibited the oxalate-induced radial segmentation of the nuclei of lymphocytes and monocytes from peripheral blood. The median inhibition was 60%. The oxalate-induced radial segmentation (RS) is thought to be due to a microtubule-dependent contraction of the intermitotic residue of the mitotic apparatus around the nucleus. CB is thought to inhibit cell locomotion and cytokinesis by a centripetal contraction of the membrane-associated contractile cell layer without subsequent relaxation. It is thus suggested that the CB inhibition of the oxalate-induced RS was due to a spatial interference of the CB-induced contraction with the formation of RS nuclei.