Altered renal hemodynamics and impaired myogenic responses in the fawn-hooded rat

• Published in: American journal of physiology. Regulatory, integrative and comparative physiology Vol. 276; no. 3; pp. 855 - R863
• Main Authors: van Dokkum, Richard P. E, Sun, Cheng-Wen, Provoost, Abraham P, Jacob, Howard J, Roman, Richard J
• Format: Journal Article
• Language: English
• Published: United States 01.03.1999
• Subjects: Animals; Glomerulosclerosis, Focal Segmental - pathology; Hemodynamics - physiology; Kidney Glomerulus - pathology; Male; Muscle Development; Muscle, Smooth, Vascular - growth & development; Punctures; Rats; Rats, Inbred Strains - physiology; Renal Artery - growth & development; Renal Circulation - physiology
• ISSN: 0363-6119; 0002-9513; 1522-1490
• DOI: 10.1152/ajpregu.1999.276.3.R855

1  Department of Pediatric Surgery, Erasmus University Medical School, 3000 DR, Rotterdam, The Netherlands; and 2  Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226 The present study examined whether an abnormality in the myogenic response of renal arterioles that impairs autoregulation of renal blood flow (RBF) and glomerular capillary pressure (P GC ) contributes to the development of renal damage in fawn-hooded hypertensive (FHH) rats. Autoregulation of whole kidney, cortical, and medullary blood flow and P GC were compared in young (12 wk old) FHH and fawn-hooded low blood pressure (FHL) rats in volume-replete and volume-expanded conditions. Baseline RBF, cortical and medullary blood flow, and P GC were significantly greater in FHH than in FHL rats. Autoregulation of renal and cortical blood flow was significantly impaired in FHH rats compared with results obtained in FHL rats. Myogenically mediated autoregulation of P GC was significantly greater in FHL than in FHH rats. P GC rose from 46 ± 1 to 71 ±   2 mmHg in response to an increase in renal perfusion pressure from 100 to 150 mmHg in FHH rats, whereas it only increased from 39 ± 2 to 53 ± 1 mmHg in FHL rats. Isolated perfused renal interlobular arteries from FHL rats constricted by 10% in response to elevations in transmural pressure from 70 to 120 mmHg. In contrast, the diameter of vessels from FHH rats increased by 15%. These results indicate that the myogenic response of small renal arteries is altered in FHH rats, and this contributes to an impaired autoregulation of renal blood flow and elevations in P GC in this strain. autoregulation; renal blood flow; glomerular capillary pressure