Renal Vascular Response to Plasma and to Known Vasoactive Substances 1

Summary

The isolated rat kidney was perfused at constant flow rate with physiological salt solution (PSS). Addition of rat plasma or a vasoactive fraction of hog plasma caused an increase in renal vascular resistance. The time course of the responses caused by these two agents was the same, but differed from that of the pressor responses caused by epinephrine, angiotensin, KCl, serotonin, or vasopressin. The ability of the vessels to respond to plasma factor was lost during perfusion with “Ca-free” PSS, whereas the ability to respond to epinephrine was not; the constrictor response produced by the plasma factor was greater during perfusion with “high-Ca” PSS, that produced by epinephrine was not.