Strophanthine (0.1 mg/kg, i. v.) and digoxin (0.1 mg/kg, i. v.) increase blood supply of the cortex and medullary layer of the kidneys of anesthetized rats and significantly raise excretion of water and sodium by the kidneys. Verapamil, a blocker of Ca(2+)-channels (0.25 mg/kg, i. v.) attenuates the increment of the blood flow in the internal zone of the cortex and external zone of the medullary layer but does not prevent the rise of diuresis and excretion of sodium with urine under the action of the above-indicated drugs. The conclusion is drawn that realization of the vasodilatory effect of cardiac glycosides in the kidneys is partially connected with a lowering of the content of Ca2+ in myofibrils whereas formation of their tubular effect does not depend on the changes in Ca2+ concentration in nephron cells.