Increased Mesenteric Blood Flow and Decreased Mesenteric Venous Compliance in Dogs with Chronic Perinephritic Hypertension

Abstract

Summary

In 10 dogs with chronic (>4 weeks) one-kidney perinephritic hypertension and in 10 uninephrectomized normotensive control dogs anesthetized with pentobarbital we measured mesenteric pressures, flows, and venous pressure-volume relationships in the collateral-free, innervated, naturally-perfused ileal loop preparation. In hypertensives, compared to normotensives, arterial pressure (P < 0.001) and mesenteric blood flow/100 g (P < 0.02) were elevated, and venous compliance was decreased. In contrast, there were no significant changes in venous pressures and total and segmental resistances in hypertensives. Mesenteric pressures, flows, resistances, and compliances in these chronically hypertensive dogs did not differ significantly (P > 0.05) from values in dogs with early (<2 weeks) perinephritic hypertension that we previously reported. Together these results indicate that in the mesentery the normal vascular resistance and increased blood flow occurring in the early stages of perinephritic hypertension in dogs persist for several weeks into the established stages, without the development of increasing resistance and decreasing flow as would have been expected if “long-term autoregulation” had taken place.