In anesthetized dogs, antidiuretic action of intravenously administered BRL 34915 (10.0~30.0 $mu$/kg) was blocked by renal denervation, whereas it was not affected by glibenclamide, a selective $K_{ATP}$ blocker, given into renal artery. Diuretic action in ipsilateral kidney produced by intrarenal administration of BRL 34915 was not influenced by renal denervation, but blocked completely by glibenclamide given into the vein. Above results suggest that the antidiuretic action of BRL 34915 is mediated by renal sympathetic nerves and the diuretic action is caused by opening of $K^+$ channel within kidney.