Effect of a kinin antagonist on renal function and haemodynamics during alterations in sodium balance in conscious normotensive rats

1990 ◽  
Vol 78 (2) ◽  
pp. 165-168 ◽  
Author(s):  
Paolo Madeddu ◽  
Nicola Glorioso ◽  
Aldo Soro ◽  
Paolo Manunta ◽  
Chiara Troffa ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Renal Blood Flow ◽  
Sodium Excretion ◽  
Filtration Rate ◽  
Sodium Intake ◽  
Urinary Sodium Excretion

1. To evaluate whether sodium intake can modulate the action of endogenous kinins on renal function and haemodynamics, a receptor antagonist of bradykinin was infused in conscious normotensive rats maintained on either a normal or a low sodium diet. 2. The antagonist inhibited the hypotensive effect of exogenously administered bradykinin. It did not change the vasodepressor effect of acetylcholine, dopamine or prostaglandin E2. 3. The antagonist did not affect mean blood pressure, glomerular filtration rate, renal blood flow or urinary sodium excretion, in rats on sodium restriction. It did not change mean blood pressure, glomerular filtration rate or urinary sodium excretion, but decreased renal blood flow, in rats on a normal sodium intake. 4. The kallikrein–kinin system has a role in the regulation of renal blood flow in rats on a normal sodium diet.

Short-term analysis of the relationship between blood pressure and urinary sodium excretion in normotensive subjects

2000 ◽  
Vol 98 (4) ◽  
pp. 495-500 ◽  
Author(s):  
Leonardo CENTONZA ◽  
Giovanna CASTOLDI ◽  
Roberto CHIANCA ◽  
Giuseppe BUSCA ◽  
Raffaello GOLIN ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Sodium Excretion ◽  
Filtration Rate ◽  
Urinary Sodium Excretion ◽  
Urinary Sodium ◽  
Short Term ◽  
Quiet Wakefulness ◽  
Normotensive Subjects

The aim of this study was to investigate whether, in the short term, physiological blood pressure changes are coupled with changes in urinary sodium excretion in normotensive subjects, maintained at fixed sodium intake and under controlled postural and behavioural conditions. Twelve normotensive subjects were recruited. For each subject, seven urine samples were collected at fixed time intervals during an overall 26 h period: late afternoon (16.00–20.00 hours), evening (20.00–24.00 hours), night (24.00–06.00 hours), quiet wakefulness (06.00–09.00 hours), morning (09.00–12.00 hours), post-prandial (12.00–15.00 hours) and afternoon (15.00–18.00 hours). Blood pressure was monitored by an ambulatory blood pressure device during the whole 26 h period. Each urine sample was used to measure urinary sodium excretion and glomerular filtration rate (creatinine clearance). Blood pressure, heart rate, urinary sodium excretion and glomerular filtration rate recorded in the daytime were higher than those measured during the night-time. A significant positive correlation between mean blood pressure and urinary sodium excretion was found during the night, over the whole 26 h period, and during two subperiods of the daytime: quiet wakefulness and the post-prandial period. The coefficient of the pressure–natriuresis curve was significantly decreased by postural changes. We conclude that, in normotensive subjects, blood pressure and urinary sodium excretion are coupled in the short term. The assumption of an upright posture can mask this relationship, presumably by activating neurohumoral factors.

Supersensitivity to norepinephrine in chronically denervated kidneys: evidence for a postsynaptic effect

1987 ◽  
Vol 65 (11) ◽  
pp. 2219-2224 ◽  
Author(s):  
J. Krayacich ◽  
R. L. Kline ◽  
P. F. Mercer
Keyword(s):  
Blood Flow ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Renal Blood Flow ◽  
Sodium Excretion ◽  
Filtration Rate ◽  
Fractional Excretion ◽  
Urine Flow ◽  
Fractional Excretion Of Sodium ◽  
Infusion Of Norepinephrine

Denervation supersensitivity in chronically denervated kidneys increases renal responsiveness to increased plasma levels of norepinephrine. To determine whether this effect is caused by presynaptic (i.e., loss of uptake) or postsynaptic changes, we studied the effect of continuous infusion of norepinephrine (330 ng/min, i.v.) and methoxamine (4 μg/min, i.v.), an α1 adrenergic agonist that is not taken up by nerve terminals, on renal function of innervated and denervated kidneys. Ganglionic blockade was used to eliminate reflex adjustments in the innervated kidney and mean arterial pressure was maintained at preganglionic blockade levels by an infusion of arginine vasopressin. With renal perfusion pressure controlled there was a significantly greater decrease in renal blood flow (−67 ± 9 vs. −33 ± 8%), glomerular filtration rate (−60 ± 9 vs. −7 ± 20%), urine flow (−61 ± 7 vs. −24 ± 11%), sodium excretion (−51 ± 15 vs. −32 ± 21%), and fractional excretion of sodium (−50 ± 9 vs. −25 ± 15%) from the denervated kidneys compared with the innervated kidneys during the infusion of norepinephrine. During the infusion of methoxamine there was a significantly greater decrease from the denervated compared with the innervated kidneys in renal blood flow (−54 ± 10 vs. −30 ± 14%), glomerular filtration rate (−51 ± 11 vs. −19 ± 17%), urine flow (−55 ± 10 vs. −39 ± 10%), sodium excretion (−70 ± 9 vs. −59 ± 11%), and fractional excretion of sodium (−53 ± 10 vs. −41 ± 10%). These results suggest that vascular and tubular supersensitivity to norepinephrine in chronically denervated kidneys is due to postsynaptic changes involving α1-adrenergic receptors.

Effects of various sympathicomimetic drugs on renal hemodynamics in normotensive and hypotensive dogs

1960 ◽  
Vol 198 (6) ◽  
pp. 1279-1283 ◽  
Author(s):  
Lewis C. Mills ◽  
John H. Moyer ◽  
Carrol A. Handley
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Renal Blood Flow ◽  
Adrenergic Receptors ◽  
Filtration Rate ◽  
Renal Hemodynamics ◽  
Marked Activity ◽  
Renal Vascular

The effects of l-epinephrine, l-norepinephrine, phenylephrine, methoxamine, metaraminol and mephentermine on renal hemodynamics were studied in six groups of dogs. Although comparable rises in blood pressure were obtained, there were marked differences in the effects on renal hemodynamics. While infusion of mephentermine led to only slight reductions in glomerular filtration rate and renal blood flow, and only a slight increase in renal vascular resistance, methoxamine produced a marked fall in flow and a marked increase in resistance. The other agents tested had effects which were intermediate between these two. The effects of these same drugs on renal hemodynamics were also compared in dogs made hypotensive by bleeding. While blood pressure increased significantly in all groups, glomerular filtration rate and renal blood flow increased significantly only during infusion of mephentermine, metaraminol and phenylephrine. Since assays relative to the inherent vasodilator properties of these agents revealed epinephrine to be the only agent with marked activity, it seems unlikely that the observed effects were due to this factor. It is concluded that the observed changes were due to a greater reactivity of renal vascular vasoconstrictor adrenergic receptors with certain sympathicomimetic drugs than those of the vasculature in general.

Effects of synthetic atrial natriuretic factor on renal function and renin release

1984 ◽  
Vol 247 (5) ◽  
pp. F863-F866 ◽  
Author(s):  
J. C. Burnett ◽  
J. P. Granger ◽  
T. J. Opgenorth
Keyword(s):  
Blood Flow ◽  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Renal Blood Flow ◽  
Atrial Natriuretic Factor ◽  
Filtration Rate ◽  
Renin Secretion ◽  
Natriuretic Factor ◽  
Atrial Natriuretic

Studies were performed in anesthetized dogs (n = 5) to determine the effects of synthetic atrial natriuretic factor on renal function and renin release. Intrarenal infusion of synthetic atrial natriuretic factor (ANF) (0.3 microgram X kg-1 X min-1) resulted in a transient increase in renal blood flow (126 +/- 8 to 148 +/- 11 ml/min). The duration of this transient vasodilation was 3.1 +/- 0.4 min. Continued infusion was followed by a slight decrease in renal blood flow (126 +/- 8 to 117 +/- 8 ml/min) and an increase in glomerular filtration rate (23.1 +/- 3.5 to 30.7 +/- 1.9 ml/min), with filtration fraction thus being increased (0.19 +/- 0.04 to 0.27 +/- 0.03). These hemodynamic alterations were associated with increases in fractional sodium excretion (0.6 +/- 0.2 to 5.8 +/- 0.8%), fractional potassium excretion (30.8 +/- 9.4 to 56.3 +/- 7.4%), fractional lithium excretion (32.2 +/- 7.1 to 60.3 +/- 5.7%), and fractional phosphate excretion (8.7 +/- 3.5 to 41.6 +/- 11.7%). Intrarenal infusion of synthetic ANF markedly suppressed renin secretion rate (295.5 +/- 84.6 to 17.2 +/- 10.6 ng/min) despite a slight reduction in arterial pressure (123 +/- 9 to 118 +/- 9 mmHg). Our studies demonstrate that synthetic ANF results in a marked natriuretic response that is in part mediated by an increase in glomerular filtration rate. The increase in fractional lithium and phosphate excretion suggests that this factor may also have an action on proximal tubule reabsorption. Further, these studies demonstrate that synthetic ANF markedly inhibits renin secretion.

Effects of the enantiomers of a new dihydropyridine derivative, S12968 and S12967, on renal functions in rats

1993 ◽  
Vol 71 (10-11) ◽  
pp. 848-853
Author(s):  
José M. López-Novoa ◽  
Inmaculada Montañés
Keyword(s):  
Blood Flow ◽  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Glomerular Filtration ◽  
Renal Blood Flow ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Hypotensive Effect

The aim of this study was to evaluate the effects of the two enantiomers of a new dihydropyridine, S12967 and S12968, on rat renal function. Male Wistar rats were injected intravenously with saline, S12967, or S12968 (0.1, 0.3, or 1 mg/kg body weight). Urinary flow, glomerular filtration rate, renal plasma flow, urinary sodium, potassium, and calcium excretions, mean arterial pressure, and renal vascular resistance were determined before and every 30 min up to 180 min after administration of the tested substance. The levogyre enantiomer S12968, at a dose of 0.3 mg/kg, induced a 4-fold increase in urinary sodium excretion, without significant or with minor changes in glomerular filtration rate, renal plasma flow, or renal blood flow. The hypotensive effect was small and nonsignificant. At 1 mg/kg, S12968 caused a profound hypotensive effect that impaired the renal function, induced marked oliguria, and decreased glomerular filtration rate and renal blood flow to almost negligible values. The dextrogyre enantiomer S12967 had much less effect on renal function. These data showing specific stereoselective renal effects are in agreement with pharmacological studies that have demonstrated that S12968 possesses a higher affinity for the dihydropyridine-binding site than its dextrogyre enantiomer, S12967.Key words: Ca channel antagonists, dihydropyridine, glomerular filtration rate, renal blood flow, natriuresis, mean arterial pressure.

The Effects of Vandellia Cordifolia on Renal Functions and Arterial Blood Pressure

1989 ◽  
Vol 17 (03n04) ◽  
pp. 203-210
Author(s):  
Huei-Yann Tsai ◽  
Ruey-Tean Chiang ◽  
Tzu-Wei Tan ◽  
Ho-Chan Chen
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Renal Blood Flow ◽  
Filtration Rate ◽  
Renal Tubules ◽  
Diuretic Effect ◽  
Renal Functions ◽  
Arterial Blood

Vandellia cordifolia (COLSM) G, DON of Scrophulariaceae (V. cordifolia) is an annual wild herb indigenous to Taiwan. It can be found in plains, low altitudes, swampy places, and paddy fields. Taiwanese folk physicians use it in "nephritis, uremia, furnucle, carbuncle." The LD50 (95% confidence limit) of the crude exract of V. codifolia given by the oral route was more than 10 g/kg in rats. By the intraperitoneal route, it was 4.6 g/kg (4.35–4.93), The extraction rate was 16.6%. We studied its effects on renal functions and blood pressure and found that (1) it had diuretic effect on normal rats, (2) it decreased glomerular filtration rate and renal blood flow on normal kidneys in rabbits, (3) it had no effects on glomerular filtration rate and renal blood flow on glycerin-induced insufficient kidneys in rabbits, (4) it had diuretic effects on both normal and glycerin-induced insufficient kidneys in rabbits, (5) it could inhibit Na+ and K+ reabsorptionn on normal and glycerin-induced insufficient kidneys in rabbits, (6) it had hypertensive effect and this effect could be blocked by phenoxybenzamine. From the above facts, we conclude that V, cordifolia had diuretic effect and it may act on renal tubules to inhibit Na+ and K+ reabsorption.

Natriuresis Following Fourth Ventricle Perfusion with High-sodium Artificial CSF

1975 ◽  
Vol 53 (3) ◽  
pp. 363-367 ◽  
Author(s):  
S. S. Passo ◽  
J. R. Thornborough ◽  
A. B. Rothballer
Keyword(s):  
Blood Pressure ◽  
Cerebrospinal Fluid ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Sodium Excretion ◽  
Fourth Ventricle ◽  
Filtration Rate ◽  
Urinary Sodium Excretion ◽  
Urinary Sodium ◽  
High Sodium

Perfusion of the fourth cerebral ventricle with high-sodium artificial cerebrospinal fluid was found to result in an increase in urinary sodium excretion in anesthetized cats. The natriuresis was accompanied by an increase in blood pressure and glomerular filtration rate. However, in animals with the changes in blood pressure and glomerular filtration rate prevented by alpha-adrenergic blockade (phenoxybenzamine), the increase in urinary sodium excretion persisted. The data suggest the presence of a neural mechanism in the vicinity of the fourth ventricle sensitive to cerebrospinal fluid sodium levels and capable of affecting urinary sodium excretion independent of changes in blood pressure or glomerular filtration rate. The possible role of the area postrema and adjacent medulla is considered.

Effect of secretin on renal blood flow, interstitial pressure, and sodium excretion

1977 ◽  
Vol 232 (2) ◽  
pp. F147-F151 ◽  
Author(s):  
G. R. Marchand ◽  
C. E. Ott ◽  
F. C. Lang ◽  
R. F. Greger ◽  
F. G. Knox
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Glomerular Filtration Rate ◽  
Renal Blood Flow ◽  
Sodium Excretion ◽  
Filtration Rate ◽  
Similar Increase ◽  
Interstitial Pressure ◽  
Polyethylene Matrix ◽  
The Relationship

Most renal vasodilators are natriuretic. However, secretin increases renal blood flow (RBF) markedly but produces only a very slight increase in sodium excretion (UNaV). To investigate this observation further, the relationship between vasodilatation, interstitial pressure (IP), and UNaV was studied in dogs. Intrarenal infusion of secretin increased RBF (delta=107+/-19 ml/min). The IP, as measured from chronically implanted polyethylene matrix capsules, was not significantly changed (delta=-0.3+/-0.5 mmHg). UNaV was slightly, although significantly, increased (delta=19+/-4 mueq/min). Following a similar increase in RBF with an intrarenal infusion of acetylcholine (ACh), IP and UNaV increased markedly (delta=8.2+/-0.8 mmHg and 174+/-23 mueq/min, respectively). Neither secretin nor ACh) altered glomerular filtration rate or blood pressure. Both secretin and ACh produced comparable increases in peritubule capillary(delta=5+/-1 and 7.5+/-1.4 mmHg, respectively) and free-flow tubule pressure (delta=7+/-2 and 9.5+/-1.4 mmHg, respectively). In summary, the usual relationship between vasodilatation and IP was dissociated during secretin infusion, whereas the relationship between IP and natriuresis was not dissociated.

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