We currently study the mechanisms of cardio-renal associations, with particular emphasis on salt, obesity and hypertension. We have developed unique methods of microdissenting and perfusing nephron segments, and demonstrated for the first time the intrinsic mechanisms by which salt-intake regulates renin release and glomerular hemodynamics. We also study the mechanisms regulating intrarenal hemodynamics using Laser methods. We propose that cardio-renal association is based on the unique micro-circulatory systems that are designed evolutionally to cope with hypoperfuiosn of vital organ such as brain, heart and kidney (Strain vessel hypothesis). We are currently investigating unique features of these circulatory systems. In addition to basic studies, we perform clinical studies assessing the roles of blood pressure management and various medications in the treatment of chronic kidney diseases, in particular, diabetic nephropathy.