Intrarenal Pressure and Exaggerated Natriuresis in Essential Hypertension
TL;DR: Intrarenal pressure, estimated by measurement of wedged renal vein pressure, was elevated in patients with essential hypertension, indicating that the higher systemic pressure in essential hypertension is transmitted beyond the arterioles and accounts for elevation of intrarenal Pressure.
Abstract: 1. Intrarenal pressure, estimated by measurement of wedged renal vein pressure, was elevated in patients with essential hypertension. Despite increased afferent arteriolar resistance, glomerular pressure was elevated indicating that the higher systemic pressure in essential hypertension is transmitted beyond the arterioles and accounts for elevation of intrarenal pressure. 2. During hypertonic saline loading in hypertensives, renal arteriolar resistance falls, resulting in further increase in intrarenal pressure. Increments in intrarenal pressure paralleled increases in sodium excretion in patients with essential hypertension during the exaggerated natriuresis and in normotensive subjects after the prolonged infusion of hypertonic saline. 3. The marked increase in intrarenal pressure which appears to be responsible for exaggerated natriuresis in essential hypertension is attributable to an altered (exaggerated) response of the renal arterioles. The data suggest that elevated intrarenal pressure may play a role in the regulation of sodium balance in patients with essential hypertension.
Citations
More filters
••
TL;DR: The affirmative position that the SHR is, indeed, an excellent model for the study of essential hypertension is taken, however, with four important caveats.
Abstract: IN 1963, Okamoto and Aoki introduced a new model of experimental hypertension that required no physiological, pharmacological, or surgical intervention. This spontaneously hypertensive rat (SHR) was developed by meticulous genetic (brother-to-sister) inbreeding that uniformly resulted in 100% of the progeny having naturally occurring hypertensive disease (Okamoto and Aoki, 1963; Okamoto et al., 1966a). Since then, several expert panels have reported that the SHR is an excellent model of experimental hypertension that could serve as a counterpart for clinical essential hypertension (Undenfriend and Spector, 1972; ILAR, 1976). In this discourse we take the affirmative position that the SHR is, indeed, an excellent model for the study of essential hypertension. We do so, however, with four important caveats. First, we recognize that it is unlikely that both forms of naturally occurring hypertension (man and rat) are identical expressions of genetically determined hypertensive disease. Second, we take the position that both forms of hypertension are polygenic in origin and that both are influenced by environmental factors. Thirdly, since the control of normal arterial pressure in both man and rat is multifactorial, it follows that certain pressor mechanisms might well operate in one form of genetic hypertension that do not necessarily occur in the other (although in both, some similar factors could be involved). This same reasoning also may be applied to hypertensive in-
511 citations
••
TL;DR: Dahl's original hypothesis, that the kidney's control of sodium excretion is paramount in the control of blood pressure, is used to form a possible explanation for the origins of essential hypertension.
393 citations
••
TL;DR: In conclusion, salt sensitivity in hypertension is associated with substantial renal, hemodynamic, and metabolic abnormalities that may enhance the risk of cardiovascular and renal morbidity.
Abstract: The mechanisms responsible for the increase in blood pressure response to high salt intake in salt-sensitive patients with essential hypertension are complex and only partially understood. A complex interaction between neuroendocrine factors and the kidney may underlie the propensity for such patients to retain salt and develop salt-dependent hypertension. The possible role of vasodilator and natriuretic agents, such as the prostaglandins, endothelium-derived relaxing factor, atrial natriuretic factor, and kinin-kallikrein system, requires further investigation. An association between salt sensitivity and a greater propensity to develop renal failure has been described in certain groups of hypertensive patients, such as blacks, the elderly, and those with diabetes mellitus. Salt-sensitive patients with essential hypertension manifest a deranged renal hemodynamic adaptation to a high dietary salt intake. During a low salt diet, salt-sensitive and salt-resistant patients have similar mean arterial pressure, glomerular filtration rate, effective renal plasma flow, and filtration fraction. On the other hand, during a high salt intake glomerular filtration rate does not change in either group, and effective renal blood flow increases in salt-resistant but decreases in salt-sensitive patients; filtration fraction and glomerular capillary pressure decrease in salt-resistant but increase in salt-sensitive patients. Salt-sensitive patients are also more likely than salt-resistant patients to manifest left ventricular hypertrophy, microalbuminuria, and metabolic abnormalities that may predispose them to cardiovascular diseases. In conclusion, salt sensitivity in hypertension is associated with substantial renal, hemodynamic, and metabolic abnormalities that may enhance the risk of cardiovascular and renal morbidity.
358 citations
••
TL;DR: The role of the kidney in blood-pressure regulation was established by TIGERSTEDT and Bergman at the close of the 19th century as discussed by the authors, who produced hypertension in dogs by injecting a cr...
Abstract: TIGERSTEDT and Bergman established a role for the kidney in blood-pressure regulation at the close of the 19th century. In a classic experiment, they produced hypertension in dogs by injecting a cr...
278 citations
••
TL;DR: It is hypothesized that the initial event in the normal tubular protein reabsorption is a binding between a free positive amino- or guanidino-group in the protein molecule and a negative site on the tubular cell surface.
Abstract: Urinary excretion of albumin, free light chains of immunoglobulins and beta-2-microglobulin was measured after injection of certain amino acids and derivatives. Substances with a positively charged...
246 citations