Effect of Nephrectomy on Arterial Reactivity in Spontaneously Hypertensive Rats

The effects of 5/6 nephrectomy on contractile and dilatory properties of the superior mesenteric artery (SMA) and internal carotid artery (ICA) segments in spontaneously hypertensive rats (SHR) were studied under isometric conditions by wire myography. Subtotal 5/6 nephrectomy (5/6 Nx) in 3-month-old rats was taken as a chronic kidney disease model. Dilatation of phenylephrine-preconstricted arterial segments was elicited by acetylcholine (AСh) or sodium nitroprusside (SNP) in the absence and presence of potassium channel blockers (tetraethylammonium, glibenclamide) or a guanylyl cyclase inhibitor methylene blue. In 5/6 Nx vs. control rats, the phenylephrine-induced contractile response of the SMA was only slightly reduced, but significantly reduced in the presence of methylene blue. In the ICA of 5/6 Nx vs. control rats, this response was significantly weaker both in the absence and presence of the potassium channel blockers and guanylyl cyclase inhibitor. 5/6 nephrectomy had no effect on the dilatory response of both arteries to AСh or SNP, however, the contractile phase of the ICA response to AСh in the presence of glibenclamide significantly decreased in 5/6 Nx, but not in control, rats. It is concluded that chronic kidney disease may attenuate endothelium-dependent and independent vasoconstriction in SHR, to a greater extent in the ICA than SMA, as well as differently affect the signaling pathways of these responses in different types of arteries, involving ATP-sensitive potassium channels in the ICA and guanylyl cyclase in the SMA.