Salt and hypertension--future directions. The comments that follow reflect the personal views of this author regarding some useful directions of research in the field of salt and hypertension. From a physiological perspective, salt sensitivity is defined, and the merits and limitations of certain animal models of hypertension used to study this issue are discussed. The need to more clearly define the mechanisms that detect sodium intake and control the renal excretion of sodium is discussed. Additionally, the need to better understand the relation between sodium homeostasis, volume regulation, and the consequences of dysfunction in these regulatory system on the arterial vasculature and interstitial matrix is emphasized. The necessity for the application of new tools and approaches in a number of investigative areas is discussed. Finally, the necessity of equally imaginative whole animal and cell/molecular research and efforts to merge and integrate the data obtained at the cellular level with that of intact systems is emphasized. 