Intrarenal blood flow distribution: effect of carotid occlusion.

In this study we have examined the influence of bilateral carotid occlusion on intrarenal blood flow distribution. Using labeled microspheres to determine intrarenal hemodynamics, bilateral carotid ligation in mannitol or saline expanded dogs resulted in an increase in outer cortical blood flow and a decrease in inner cortical flow. Total renal blood flow and glomerular filtration rate did not change significantly during carotid occlusion whereas the average mean arterial blood pressure rose from 130 to 166 mmHg. Inner cortical flow resistance increased substantially after carotid occlusion; outer cortical resistance was unchanged. These results suggest that bilateral carotid occlusion selectively activates inner cortical renal sympathetic fibers.