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J M Lopez-Novoa

Publications and source records attributed to J M Lopez-Novoa.

28 records · Page 2Linked to original sources
PubMed1985

Effect of captopril infusion on systemic and renal haemodynamics in conscious hypertensive rats with chronic, progressive aortic ligation.

The effect of the converting enzyme inhibitor captopril (5 mg (kg bwt)-1) on systemic and renal haemodynamics has been studied in conscious rats in which a progressive hypertension has been induced by progressive aortic ligation (AL) between the renal arteries, and in a sham-operated (SO) group. Cardiac output (CO), organ blood flow and vascular resistances have been measured using radioactive microsphaeres. Captopril infusion caused increases in CO in both groups of rats, but the increase was higher in SO (9.2 +/- 0.7%) than in AL rats (5.2 +/- 0.6%; P less than 0.005). Plasma renin concentrations were similar in both groups but increased more in AL (10.3 microIU +/- 1.0) than in SO (5.81 microIU +/- 0.62; P less than 0.05) after captopril. Captopril induced also a larger decrease in arterial pressure (36 +/- 4 mmHg), and of the pressure gradient across the stenosis (19 +/- 3) mmHg in AL than in SO rats (5.6 +/- 1.4 and 1.1 +/- 1.3 mmHg, P less than 0.005 for both cases). Vascular resistance of the kidney above the ligature decreased more in AL than in SO rats, but this difference was not observed in the other kidney. From these data it can be concluded that captopril has an acute hypotensive effect despite the normal renin levels of this model of chronic hypertension. In addition, blood flow to the high-pressure perfused kidney seems to be dependent on the increased renin production by the contralateral kidney.

Animals↗
PubMed1982

Functional compensatory changes after unilateral nephrectomy in rats. General and intrarenal hemodynamic alterations.

Cardiac output (CO), total peripheral resistance (TPR), renal blood flow (RBF), renal vascular resistance (RVR) and intrarenal blood flow distribution have been measured 48 h after unilateral (right) nephrectomy (UNX) and in sham-operated rats (SO). Glomerular filtration rate (GFR) and renal plasma flow (RPF) were determined using standard inulin and PAH clearances. Superficial single nephron GFR (SNGFR) was measured by free-flow micropuncture techniques. Extracellular fluid volume (ECV) and plasma volume (PV) were also determined. UNX rats showed increases of 17.4% in remnant kidney GFR and 34.5% in RPF. Filtration fraction was decreased to 0.27 +/- 0.01 (control value 0.31 +/- 0.01; p less than 0.0025). SNGFR was 45% higher in UNX rats and the ratio SNGFR/GFR increased by 28%. Cardiac output also increased (33.6 +/- 1.0 for UNX rats; 28.0 +/- 1.2 ml/min/100 g BW for SO rats; p less than 0.0025) accompanied by a corresponding fall (20%) in TPR. Left kidney RBF increased by 22%, whereas RVR decreased by 21%. Blood flow through individual glomeruli increased in the outer and inner cortex and was unchanged in the midcortex. In conclusion, 48 h after unilateral nephrectomy, rats showed a hyperdynamic circulatory state with increased CO and decreased TPR; this could be involved in the acute adaptive functional and renal changes reported after uninephrectomy.

Animals↗
PubMed1978

Sodium excretion after bilateral adrenalectomy in rats with experimental cirrhosis.

Bilateral adrenalectomy (ADX) or a sham procedure was performed in cirrhotic and control rats. After ADX, controls increased their sodium excretion with respect to the basal values but cirrhotics did not. When sodium-loaded, the ADX cirrhotic rats retained a significant amount of the load. These data do not support a primary role of aldosterone in the impaired sodium handling by cirrhotic rats.

Adrenalectomy↗
PubMed1978

Alleviation of experimental acute renal failure in rats by reduction of renal mass.

An acute renal failure (ARF) has been produced by glycerol injection on rats unilaterally nephrectomized 48 h before. Rats with reduced renal mass showed polyuria and significantly lower azotemia than controls with ARF. This data might be explained by increased glomerular plasma flow in the remnant kidney previous to ARF induction.

Acute Kidney Injury↗
PubMed1978

Partial protection against acute renal failure in rats with reduced renal mass.

Glycerol-induced acute renal failure (ARF) was studied in rats with two degrees of reduced renal mass (RRM). RRM animals, when compared with sham-operated animals, showed a partial protection against this model of ARF. This protection depends on a less marked decrease in glomerular filtration rate and renal plasma flow after ARF induction in RRM rats, with an increased filtration fraction. It is suggested that glycerol injection in RRM rats could induce a mainly efferent arteriolar vasoconstriction, in contrast to control rats, whose glomerular arteriolar vasoconstriction is mainly afferent.

Acute Kidney Injury↗
PubMed1977

A micropuncture study of salt and water retention in chronic experimental cirrhosis.

The object of this study was to localize increased sodium resorption in rats with chronic hepatic cirrhosis. Cirrhosis was induced by the administration of phenobarbital and carbon tetrachloride. The animals retained salt and water after loading and showed edema and ascites. Salt and water balance, clearance, and micropuncture tests were performed. Five or six weeks after the start of procedures to induce injury, the rats were unable to excrete salt and water loads promptly. Urine flow and sodium concentration were significantly less in cirrhotic rats with edema and ascites than in the normal controls. The glomerular filtration rate was slightly lower in the right, nonmicropunctured kidney but was the same in the left. The nephron glomerular filtration rates of surface nephrons were equal in both the experimental and control rats. The fractional proximal resorption rate was notably greater in cirrhotic rats, as was the total proximal nephron resorption rate. That increased proximal resorption alone might account for diminished sodium and water excretion cannot be demonstrated from this study, although we believe that major evidence is provided of the importance of proximal resorption in this phenomenon.

Animals↗
PubMed1977

Papaverine effect on postischemic acute renal failure in rats.

The effect of papaverine at the time of starting a post-ischemic acute renal failure in rats has been studied. Papaverine administration increases diuresis and reduces serum urea and creatinine levels. The primary role of hemodynamic disorders as responsible for the diminished glomerular filtration rate is supported by the reduced severity of acute renal failure when this vasodilator agent is administered.

Acute Kidney Injury↗
PubMed1977

Negative effect of frusemide pretreatment in glycerol induced acute renal failure.

It is commonly assumed that the decrease in the effective circulatory volume (ECV) is the major event in acute renal failure (ARF) and the preferential ischemia of the cortex another major modification. Frusemide has been given to try to prevent this change in glycerol-induced ARF because of its effect in redistributing renal blood flow from medulla to cortex. Isontonic saline was also tried to avoid the ECV depletion. The pretreatment with frusemide not only fails to protect against the ARF but increases its severity. Isotonic saline adminstration and replacement of urinary losses almost prevent glycerol-induced ARF but when both isotonic saline frusemide are administered together their effect is only a slight increase in the excretion rate of urea and creatinine during the first days of the experiment. The importance of the changes in the ECV or a possible direct action of frusemide on the renin-angiotensin axis are discussed. There is a good correlation between plasma creatinine levels and interstitial oedema. The importance of the oedema in the maintenance of ARF is discussed.

Acute Kidney Injury↗