Vasocontractile action of daunorubicin.

Daunorubicin (35.5-142 mumol L-1) induced in rat aortic strips a contraction with slow onset and a gradual development of tension on which neither phentolamine nor bromophenacyl bromide pretreatment had an effect. The contraction was not altered by removal of the endothelium but it was suppressed in calcium-free solution or by preincubation with nifedipine. These results suggest that daunorubicin directly stimulates vascular smooth muscle and induces a contractile response which is mainly dependent upon extracellular calcium.