Central and Regional Hemodynamics During the Acute Onset of Renal Hypertension in Rats

Abstract

The purpose of this study was to quantitate the regional changes in flow and resistance which occur during the acute onset of two-kidney, one clip renal hypertension. Anesthetized rats were implanted with a Doppler flow probe and balloon occluder on one renal artery. To produce acute hypertension, the occluder was inflated to reduce renal flow velocity by 50%. After 90 minutes, mean arterial pressure increased 25% above the prestenosis control period value as a result of a 22% increase in peripheral resistance. Regional flows and resistances were determined prior to and 90 minutes after renal artery stenosis by Injection of labelled microspheres into the left ventricle. Our major findings were that: 1) the regional hemodynamic changes in flow and resistance are unevenly distributed among individual organs; and 2) the major site of increased resistance resides in the splanchnic circulation with the largest increases occurring in the small intestine.

Key Words:

• Acute Goldblatt hypertension
• Cardiac output
• Total peripheral resistance
• Resistance distribution
• Regional flows
• Splanchnic circulation