Attenuated contractility in afferent arterioles during development of proteinuria in two‐kidney, one‐clip hypertensive rats

Abstract

AimsWe wanted to investigate the contractile properties of afferent arterioles (AAs) from two‐kidney, one‐clip (2K1C) hypertensive rats before and during development of proteinuria, and whether these vessels behave differently in outer and inner renal cortex.MethodsWistar rats were subjected to either a 2K1C or sham operation. Blood pressure was measured and urine was sampled before the rats were killed after 18 ± 4 weeks. AAs were isolated from outer and inner renal cortex of the non‐clipped kidney of the 2K1C and from both kidneys of the sham rats with the agarose infusion technique. The AAs were stimulated with angiotensin II (AngII) in increasing concentrations (10−10 M to 10−7 M), and degree of contraction was recorded.ResultsThe preliminary results are based on AAs isolated from 9 rats (Sham: 3, 2K1C without proteinuria (2K1C Prot−): 2, and 2K1C with proteinuria (2K1C Prot+): 4). There was no difference in mean arterial pressure between the 2K1C with and without proteinuria (184 ± 6 vs. 178 ±8 mmHg, NS).We found a significantly attenuated response to AngII 10−7 M in the superficial AAs from both hypertensive groups compared to sham. However, in the AAs from the juxtamedullary nephrons there was a preserved response in the vessels from the 2K1C rats without proteinuria.ConclusionLoss of contractile properties of AAs in deep cortex may contribute to development of renal damage and proteinuria in this model.