l    Maintenance of Relatively Constant Intraglomerular Pressure by Renal Autoregulation despite Variations in Mean Arterial Pressure.
l
Palmer H: NEJM  2002;347:16
In chronic hypertension, the curve showing the relation of the intraglomerular pressure to the renal perfusion pressure (or mean arterial pressure) is shifted to the right. With the development of chronic renal failure, renal autoregulation changes in such a way that the intraglomerular pressure begins to vary more directly with changes in the mean arterial blood pressure. When this change occurs, the normal sigmoidal relation becomes progressively more linear. As a result, increases in the mean arterial pressure cause exaggerated increases in the intraglomerular pressure, whereas declines in the mean arterial pressure cause exaggerated decreases. Because of the rightward shift in the lower end of the curve, antihypertensive therapy may be accompanied by a decline in the glomerular filtration rate at a level of blood pressure that would not affect a normal person. Renal dysfunction in this setting is hemodynamic in origin and reflects a lower intraglomerular pressure.