Interaction of renal prostaglandins with the renin-angiotensin and renal adrenergic nervous systems in healthy subjects during dietary changes in sodium intake

1985 ◽  
Vol 68 (4) ◽  
pp. 387-393 ◽  
Author(s):  
Herbert J. Kramer ◽  
Bruno Stinnesbeck ◽  
Georg Klautke ◽  
Jochen Kipnowski ◽  
Dietrich Klingmueller ◽  
...  

1. In six healthy subjects the role of renal prostaglandins (PG) in modulating the actions of the renin-angiotensin and renal adrenergic nervous systems on renal function was investigated. 2. During high dietary sodium intake (350 mmol/day) for 4 days no changes in urinary excretion of PGE2, PGF2α, noradrenaline or adrenaline were noted, whereas plasma renin activity (PRA) and urinary aldosterone excretion were suppressed. 3. After 4 days of low sodium intake (35 mmol/day) urinary excretion of PGE2, aldosterone and noradrenaline, as well as PRA, had significantly increased. 4. Inhibition of PG synthesis with indomethacin (2 mg/kg body weight) had no effects on renal function on day 5 of high sodium intake. Despite suppression of PRA and urinary aldosterone, indomethacin significantly reduced p-aminohippurate (PAH) clearance, glomerular filtration rate (GFR) and urinary sodium excretion on day 5 of low sodium intake, when urinary noradrenaline excretion remained high. 5. The results point to the crucial role of the renal adrenergic nervous system in controlling renal vascular resistance and sodium conservation in healthy subjects during low sodium intake, which is unmasked when renal PG synthesis is blocked by indomethacin. Enhanced renal PG synthesis during sodium restriction therefore not only attenuates the vascular and tubular effects of the renin-angiotensin system but, more importantly, also those of the highly stimulated renal adrenergic nervous system.

1992 ◽  
Vol 70 (5) ◽  
pp. 733-734 ◽  
Author(s):  
J. Michael Wyss

The kidney is the most highly innervated peripheral organ, and both the excretory and endocrine functions of the kidney are regulated by renal nerve activity. The kidney plays a dominant role in body fluid homeostasis, blood ionic concentration, and pH and thereby contributes importantly to systemic blood pressure control. Early studies suggested that the neural-renal interactions were responsible only for short-term adjustments in renal function, but more recent studies indicate that the renal nerves may be a major contributor to chronic renal defects leading to established hypertension and (or) renal disease. The neural-renal interaction is also of considerable interest as a model to elucidate the interplay between the nervous system and peripheral organs, since there is abundant anatomical and physiological information characterizing the renal nerves. The investigator has easy access to the renal nerves and the neural influence on renal function is directly quantifiable both in vivo and in vitro. In this symposium that was presented at the 1990 annual convention of the Society for Neuroscience in St. Louis, Missouri, three prominent researchers evaluate the most recent progress in understanding the interplay between the nervous system and the kidney and explore how the results of these studies relate to the broader questions concerning the nervous system's interactions.First, Luciano Barajas examines the detailed anatomy of the intrarenal distribution of the efferent and afferent renal nerves along the nephron and vasculature, and he evaluates the physiological role of each of the discrete components of the innervation. His basic science orientation combined with his deep appreciation of the clinical consequence of the failure of neural-renal regulation enhances his discussion of the anatomy. Ulla C. Kopp discusses the role of the renorenal reflex, which alters renal responses following stimulation of the contralateral kidney. She also considers her recent findings that efferent renal nerve activity can directly modify sensory feedback to the spinal cord from the kidney. Finally, J. Michael Wyss examines the functional consequences of neural control of the kidney in health and disease. Although the nervous system has often been considered as only an acute regulator of visceral function, current studies into hypertension and renal disease suggest that neural-renal dysfunction may be an important contributor to chronic diseases.Together, these presentations examine most of the recent advances in the area of neural-renal interactions and point out how these data form a basis for future research into neuronal interactions with all visceral organs. The relative simplicity of the neural-renal interaction makes this system an important model with which to elucidate all neural-peripheral and neural-neural interactions.


1992 ◽  
Vol 2 (9) ◽  
pp. 1371-1387 ◽  
Author(s):  
J C Romero ◽  
V Lahera ◽  
M G Salom ◽  
M L Biondi

The role of nitric oxide in renal function has been assessed with pharmacologic and physiologic interventions. Pharmacologically, the renal vasodilation and, to some extent, the natriuresis produced by endothelium-dependent vasodilators such as acetylcholine and bradykinin are mediated by nitric oxide and also by prostaglandins. However, prostaglandins and nitric oxide do not participate in the renal effects produced by endothelium-independent vasodilators such as atrial natriuretic peptide, prostaglandin I2, and nitroprusside. Physiologically, nitric oxide and prostaglandins exert a strong regulation on the effects produced by changes in renal perfusion pressure. Increments in renal perfusion pressure within the range of RBF autoregulation appear to inhibit prostaglandin synthesis while simultaneously enhancing the formation of nitric oxide. Nitric oxide modulates autoregulatory vasoconstriction and at the same time inhibits renin release. Conversely, a decrease of renal perfusion pressure to the limit of or below RBF autoregulation may inhibit the synthesis of nitric oxide but may trigger the release of prostaglandins, whose vasodilator action ameliorates the fall in RBF and stimulates renin release. Nitric oxide and prostaglandins are also largely responsible for mediating pressure-induced natriuresis. However, unlike prostaglandins, mild impairment of the synthesis of nitric oxide in systemic circulation produces a sustained decrease in sodium excretion, which renders blood pressure susceptible to be increased during high-sodium intake. This effect suggests that a deficiency in the synthesis of nitric oxide could constitute the most effective single disturbance to foster the development of a syndrome similar to that seen in salt-sensitive hypertension.


2002 ◽  
Vol 13 (4) ◽  
pp. 1025-1033
Author(s):  
Frank G. H. van der Kleij ◽  
Paul E. de Jong ◽  
Rob H. Henning ◽  
Dick de Zeeuw ◽  
Gerjan Navis

ABSTRACT. Angiotensin-converting enzyme (ACE) activity is increased in the DD genotype, but the functional significance for renal function is unknown. Blunted responses of BP and proteinuria to ACE inhibition among DD renal patients during periods of high sodium intake were reported. It was therefore hypothesized that sodium status affects the phenotype in the ACE I/D polymorphism. The effects of angiotensin I (AngI) and AngII among 27 healthy subjects, with both low (50 mmol sodium/d) and liberal (200 mmol sodium/d) sodium intakes, were studied. Baseline mean arterial pressure (MAP) values, renal hemodynamic parameters, and renin-angiotensin system parameters were similar for all genotypes with either sodium intake level. With liberal sodium intake, the increases in MAP, renal vascular resistance, and aldosterone levels during AngI infusion (8 ng/kg per min) were significantly higher for the DD genotype, compared with the ID and II genotypes (all parameters presented as percent changes ± 95% confidence intervals), with mean MAP increases of 22 ± 2% (DD genotype), 13 ± 5% (ID genotype), and 12 ± 6% (II genotype) (P < 0.05), mean increases in renal vascular resistance of 100.1 ± 19.7% (DD genotype), 73.0 ± 16.3% (ID genotype), and 63.2 ± 16.9% (II genotype) (P < 0.05), and increases in aldosterone levels of 650 ± 189% (DD genotype), 343 ± 71% (ID genotype), and 254 ± 99% (II genotype) (P < 0.05). Also, the decrease in GFR was more pronounced for the DD genotype, with mean decreases of 17.9 ± 4.7% (DD genotype), 8.8 ± 3.4% (ID genotype), and 6.4 ± 5.9% (II genotype) (P < 0.05). The effective renal plasma flow, plasma AngII concentration, and plasma renin activity values were similar for the genotypes. In contrast, with low sodium intake, the responses to AngI were similar for all genotypes. The responses to AngII were also similar for all genotypes, with either sodium intake level. In conclusion, the responses of MAP, renal hemodynamic parameters, and aldosterone concentrations to AngI are enhanced for the DD genotype with liberal but not low sodium intake. These results support the presence of gene-environment interactions between ACE genotypes and dietary sodium intake.


BMJ ◽  
2019 ◽  
pp. l772 ◽  
Author(s):  
Martin O’Donnell ◽  
Andrew Mente ◽  
Sumathy Rangarajan ◽  
Matthew J McQueen ◽  
Neil O’Leary ◽  
...  

AbstractObjectiveTo evaluate the joint association of sodium and potassium urinary excretion (as surrogate measures of intake) with cardiovascular events and mortality, in the context of current World Health Organization recommendations for daily intake (<2.0 g sodium, >3.5 g potassium) in adults.DesignInternational prospective cohort study.Setting18 high, middle, and low income countries, sampled from urban and rural communities.Participants103 570 people who provided morning fasting urine samples.Main outcome measuresAssociation of estimated 24 hour urinary sodium and potassium excretion (surrogates for intake) with all cause mortality and major cardiovascular events, using multivariable Cox regression. A six category variable for joint sodium and potassium was generated: sodium excretion (low (<3 g/day), moderate (3-5 g/day), and high (>5 g/day) sodium intakes) by potassium excretion (greater/equal or less than median 2.1 g/day).ResultsMean estimated sodium and potassium urinary excretion were 4.93 g/day and 2.12 g/day, respectively. After a median follow-up of 8.2 years, 7884 (6.1%) participants had died or experienced a major cardiovascular event. Increasing urinary sodium excretion was positively associated with increasing potassium excretion (unadjusted r=0.34), and only 0.002% had a concomitant urinary excretion of <2.0 g/day of sodium and >3.5 g/day of potassium. A J-shaped association was observed of sodium excretion and inverse association of potassium excretion with death and cardiovascular events. For joint sodium and potassium excretion categories, the lowest risk of death and cardiovascular events occurred in the group with moderate sodium excretion (3-5 g/day) and higher potassium excretion (21.9% of cohort). Compared with this reference group, the combinations of low potassium with low sodium excretion (hazard ratio 1.23, 1.11 to 1.37; 7.4% of cohort) and low potassium with high sodium excretion (1.21, 1.11 to 1.32; 13.8% of cohort) were associated with the highest risk, followed by low sodium excretion (1.19, 1.02 to 1.38; 3.3% of cohort) and high sodium excretion (1.10, 1.02 to 1.18; 29.6% of cohort) among those with potassium excretion greater than the median. Higher potassium excretion attenuated the increased cardiovascular risk associated with high sodium excretion (P for interaction=0.007).ConclusionsThese findings suggest that the simultaneous target of low sodium intake (<2 g/day) with high potassium intake (>3.5 g/day) is extremely uncommon. Combined moderate sodium intake (3-5 g/day) with high potassium intake is associated with the lowest risk of mortality and cardiovascular events.


2005 ◽  
Vol 289 (3) ◽  
pp. R633-R641 ◽  
Author(s):  
Gerald F. DiBona

Cannon equated the fluid matrix of the body with Bernard’s concept of the internal environment and emphasized the importance of “the safe-guarding of an effective fluid matrix.” He further emphasized the important role of the autonomic nervous system in the establishment and maintenance of homeostasis in the internal environment. This year’s Cannon Lecture discusses the important role of the renal sympathetic nerves to regulate various aspects of overall renal function and to serve as one of the major “self-regulatory agencies which operate to preserve the constancy of the fluid matrix.”


1980 ◽  
Vol 95 (2) ◽  
pp. 172-176 ◽  
Author(s):  
Stefan Zgliczyński ◽  
Marek Kaniewski

Abstract. In order to elucidate the role of the adrenergic nervous system in the mechanism of TSH release in men the effects of α- and β-receptors blocking agents were studied in 11 healthy volunteers. Phentolamine administetred iv as a bolus injection in a dose of 10 mg, significantly lowered the TSH release in basal condition and in response to TRH stimulation. However, propranolol in a dose of 0.1 mg/kg administered in the same fashion as phentolamine had no effect on the TSH secretion. The results obtained suggest that the α-receptors of the adrenergic system are involved in the physiological mechanism which stimulates TSH release in men.


2011 ◽  
Vol 24 (2) ◽  
pp. 209-217 ◽  
Author(s):  
L. P. Svetkey ◽  
E. L. Harris ◽  
E. Martin ◽  
W. M. Vollmer ◽  
G. T. Meltesen ◽  
...  

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