The influence of renal nerves on electrolyte excretion in conscious and anesthetized rats fed or fasted overnight

1990 ◽  
Vol 68 (4) ◽  
pp. 524-530 ◽  
Author(s):  
P. F. Mercer ◽  
R. L. Kline
Keyword(s):  
Renal Nerves ◽  
Potassium Excretion ◽  
Electrolyte Excretion ◽  
Renal Nerve ◽  
Conscious Rats ◽  
Anesthetized Rats ◽  
Norepinephrine Turnover ◽  
Renal Nerve Activity ◽  
Fasted Rats

The role of the renal nerves in the electrolyte excretion of rats fed or fasted overnight was determined in conscious rats and anesthetized (Inactin) and surgically prepared rats. In conscious rats sodium excretion, as measured in a 1-h urine collection period after feeding or fasting overnight, was decreased with fasting with or without renal nerves. Renal nerve activity, as measured by norepinephrine turnover (inhibition of tyrosine hydroxylase by α-methyl-p-tyrosine), was not different between conscious fed or fasted rats and increased to the same extent in fed and fasted rats when anesthetized and surgically prepared. Anesthetized, surgically prepared rats infused with 5.0% glucose showed a denervation natriuresis if rats were fed overnight, but not if they had been fasted overnight. Potassium excretion in conscious and anesthetized rats was lower in fasted rats than fed rats with or without renal nerves. These data suggest (i) renal nerves are not involved in the renal response to an overnight fast in conscious rats, and (ii) in anesthetized, surgically prepared rats renal sympathetic tone is enhanced and denervation natriuresis occurs if rats are fed but not if fasted. Potassium excretion is a reflection of whether rats are fed or fasted and not whether they have renal nerves.Key words: kidney, fasting, sodium, renal nerves.

Neuronal regulation of renal function: A model system for nervous system interactions

1992 ◽  
Vol 70 (5) ◽  
pp. 733-734 ◽  
Author(s):  
J. Michael Wyss
Keyword(s):  
Nervous System ◽  
Renal Function ◽  
Renal Disease ◽  
Easy Access ◽  
Renal Nerves ◽  
Clinical Consequence ◽  
Nerve Activity ◽  
Renal Nerve ◽  
Renal Nerve Activity

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.

Lack of effect of chronic renal denervation on altered sodium reabsorption during increased ureteral pressure

1980 ◽  
Vol 58 (5) ◽  
pp. 477-483 ◽  
Author(s):  
D. R. Wilson ◽  
M. Cusimano ◽  
U. Honrath
Keyword(s):  
Isotonic Saline ◽  
Urine Osmolality ◽  
Tubular Reabsorption ◽  
Renal Nerves ◽  
Sodium Reabsorption ◽  
Nerve Activity ◽  
Renal Nerve ◽  
Water Excretion ◽  
Renal Nerve Activity

The role of the renal nerves in the altered sodium reabsorption which occurs during increased ureteral pressure was studied using clearance techniques in anaesthetized rats undergoing diuresis induced by isotonic saline infusion. In rats with a sham denervated kidney, an ipsilateral increase in ureteral pressure to 20 cm H2O resulted in a marked and significant decrease in sodium and water excretion, increased fractional sodium reabsorption, and increased urine osmolality with no significant change in glomerular filtration rate. A similar significant ipsilateral increase in tubular reabsorption of sodium occurred in rats with chronically denervated kidneys during increased ureteral pressure. The changes in tubular reabsorption were rapidly reversible after return of ureteral pressure to normal. These experiments indicate that enhanced tubular reabsorption of sodium during an ipsilateral increase in ureteral pressure is not mediated by increased renal nerve activity. During the antinatriuresis of increased ureteral pressure there was a decrease in the fractional reabsorption of sodium from the opposite normal kidney. The role of the renal nerves in this compensatory change in function in the opposite kidney was studied in two further groups of animals. The renal response to a contralateral increase in ureteral pressure was similar in denervated and sham-denervated kidneys. The results indicate that altered renal nerve activity, through ipsilateral or contralateral renorenal reflexes, is not responsible for the changes in tubular reabsorption of sodium which occur during increased ureteral pressure induced by partial ureteral obstruction.

Activation of afferent renal nerves by intrarenal bradykinin in conscious rats

1984 ◽  
Vol 247 (6) ◽  
pp. R1003-R1008 ◽  
Author(s):  
J. F. Smits ◽  
M. J. Brody
Keyword(s):  
Cardiovascular Effects ◽  
Renal Nerves ◽  
Renal Nerve ◽  
Conscious Rats ◽  
Arterial Blood ◽  
Regional Hemodynamics ◽  
Renal Nerve Activity ◽  
The Right ◽  
Conscious Animals ◽  
Intact Rats

Bradykinin was infused intravenously and into the right renal artery of conscious rats that were chronically instrumented with catheters and miniaturized pulsed-Doppler flow probes. The effects on regional hemodynamics were compared with those in animals in which the infused kidney was denervated as well as in animals anesthetized with pentobarbital sodium. In intact rats bradykinin (1 microgram/min) caused an immediate increase in mean arterial blood pressure (MAP, 27 +/- 4 mmHg), heart rate (HR, 67 +/- 11 beats/min), mesenteric resistance (MR, 32 +/- 10%), and both right (RRR, 42 +/- 14%) and left renal resistance (LRR 21 +/- 8%). These effects were significantly different from those during intravenous infusion of the same dose of bradykinin (MAP, 6 +/- 3 mmHg; HR, 31 +/- 7 beats/min; MR, -21 +/- 5%; RRR, 8 +/- 4%; LRR, 6 +/- 3%). Pentobarbital greatly attenuated the responses to intrarenal bradykinin. In conscious animals denervation of the infused kidney completely abolished the cardiovascular effects of intrarenal bradykinin. In a separate group of animals, chlorisondamine (7.5 mg/kg iv) completely blocked the increases in MAP and HR during intrarenal bradykinin (1 microgram/min). It is concluded that selective renal administration of bradykinin alters afferent renal nerve activity and that this results in hemodynamic changes consistent with efferent sympathetic activation.

scholarly journals Renal Nerve Deafferentation Attenuates the Fall in GFR during Intravenous Infusion of Furosemide in Anesthetized Rats

2020 ◽  
Vol 45 (1) ◽  
pp. 70-83 ◽  
Author(s):  
Magali Araujo ◽  
Glenn Solis ◽  
William J. Welch ◽  
Christopher S. Wilcox
Keyword(s):  
Proximal Tubule ◽  
Volume Replacement ◽  
Tubuloglomerular Feedback ◽  
Renal Nerves ◽  
Volume Depletion ◽  
Renal Nerve ◽  
At1 Receptors ◽  
Anesthetized Rats ◽  
Renal Nerve Activity ◽  
Renal Vascular

Introduction: Furosemide reduces the glomerular filtration rate (GFR) and increases the renal vascular resistance (RVR) despite inhibiting tubuloglomerular feedback but increases proximal tubule pressure, renin release, and renal nerve activity. Objective: This study tested the hypothesis that the fall in GFR with furosemide is due to volume depletion or activation of angiotensin type 1 (AT1) receptors or renal nerves. Methods: Furosemide was infused for 60 min at 1.0 mg·kg−1·h−1 in groups of 5–8 anesthetized rats. Additional groups received intravenous volume replacement to prevent fluid and Na+ losses or volume replacement plus losartan or plus sham denervation or plus renal denervation or renal nerve deafferentation. Results: At 60 min of infusion, furosemide alone reduced the GFR (–37 ± 4%; p < 0.01). This fall was not prevented by volume replacement or pretreatment with losartan, although losartan moderated the increase in RVR with furosemide (+44 ± 3 vs. +82 ± 7%; p < 0.01). Whereas the GFR fell after furosemide in rats after sham procedure (–31 ± 2%), it was not changed significantly after prior renal deafferentation. Proximal tubule pressure increased significantly but returned towards baseline over 60 min of furosemide, while urine output remained elevated, and GFR and renal blood flow depressed. Conclusions: The fall in GFR over 60 min of furosemide infusion is independent of volume depletion or activation of AT1 receptors but is largely dependent on renal afferent nerves.

Renal nerve activity in conscious rats during volume expansion and depletion

1985 ◽  
Vol 248 (1) ◽  
pp. F15-F23 ◽  
Author(s):  
G. F. DiBona ◽  
L. L. Sawin
Keyword(s):  
Volume Expansion ◽  
Sodium Intake ◽  
Dietary Sodium ◽  
Right Atrial ◽  
Renal Nerves ◽  
Volume Depletion ◽  
Nerve Activity ◽  
Renal Nerve ◽  
Conscious Rats ◽  
Renal Nerve Activity

The role of renal nerve activity (RNA) in the renal response to isotonic saline volume expansion and furosemide-induced volume depletion was studied in conscious rats consuming a low (LNa), normal (NNa), or high (HNa) dietary sodium intake. In the control state, right atrial pressure (RAP) and UNa V were directly related and RNA was inversely related to dietary sodium intake, being 12.9 +/- 0.7, 10.9 +/- 1.1 and 8.7 +/- 0.6 units in LNa, NNa, and HNa rats, respectively. During volume expansion, RAP and UNa V increased and RNA decreased in all three dietary groups; however, the peak increase in UNa V was greater in the LNa (88 +/- 6 mueq/min) than NNa (34 +/- 9 mueq/min) or HNa (32 +/- 6 mueq/min) rats. The greater natriuresis in LNa was associated with a larger decrease in RNA in LNa (-6.1 +/- 0.5 units) than in NNa (-3.4 +/- 0.4 units). The greater contribution of inhibition of RNA to the increased natriuretic response to volume expansion in LNa compared with NNa rats was further examined in renal denervated animals. Bilateral renal denervation substantially reduced the natriuretic response to volume expansion in LNa rats (-70%) but had no significant effect in NNa rats (-15%). During volume depletion, RAP decreased, whereas UNa V and RNA increased in all three dietary groups. After the peak of the furosemide natriuresis, UNa V was lower in the LNa rats than in the NNa or HNa rats at any level of increased RNA, consistent with a role for the renal nerves in the normal renal adaptive response to sodium/volume depletion.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential effects of hemorrhage on adrenal and renal nerve activity in anesthetized rats

1990 ◽  
Vol 259 (4) ◽  
pp. H1134-H1141 ◽  
Author(s):  
H. Togashi ◽  
M. Yoshioka ◽  
M. Tochihara ◽  
M. Matsumoto ◽  
H. Saito
Keyword(s):  
Renal Nerves ◽  
Dependent Manner ◽  
Endogenous Opioid System ◽  
Endogenous Opioid ◽  
Nerve Activity ◽  
Renal Nerve ◽  
Differential Effects ◽  
Arterial Blood ◽  
Anesthetized Rats ◽  
Renal Nerve Activity

Evidence that sympathetic outflow to organs with different functions reacts nonuniformly to various stimuli has accumulated. To clarify the difference in outflow characteristics of adrenal and renal nerves, the neural and neurochemical mechanisms involved in the response to hemorrhage were examined in anesthetized rats. Hemorrhage (2, 5, and 10 ml/kg) increased adrenal nerve activity (ANA) and decreased renal nerve activity (RNA) in a bleeding volume-dependent manner, accompanied with a decrease in mean arterial blood pressure and heart rate. Bilateral vagotomy attenuated the response in ANA and completely abolished the response in RNA. Sinoaortic denervation (SAD) and vagotomy combined with SAD inversely decreased ANA during hemorrhage. However, SAD appears to have no effect on the response in RNA, which was completely abolished by combined denervation. Our results suggest that the differential effects of hemorrhage on ANA and RNA may be due to different contributions via the afferent neural pathways from the baro- and cardiopulmonary receptors. Because naloxone attenuated the dissociated response to hemorrhage, the endogenous opioid system may be involved.

Functional response to graded increases in renal nerve activity during hypoxia in conscious rabbits

1996 ◽  
Vol 271 (6) ◽  
pp. R1489-R1499 ◽  
Author(s):  
S. C. Malpas ◽  
A. Shweta ◽  
W. P. Anderson ◽  
G. A. Head
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Sodium Excretion ◽  
Gas Mixtures ◽  
Renin Activity ◽  
Renal Nerves ◽  
Nerve Activity ◽  
Renal Nerve ◽  
Renal Nerve Activity ◽  
Conscious Rabbits

Changes in renal sympathetic nerve activity (SNA) are postulated to influence renal function in selective ways, such that different levels of activation produce particular renal responses, initially in renin release, then sodium excretion, with changes in renal hemodynamics occurring only with much greater stimulus intensities. The aim of this study was to determine the renal hemodynamic and excretory responses to graded physiological increases in renal SNA induced by breathing different hypoxic gas mixtures. Experiments were performed in seven conscious rabbits subjected to four gas mixtures (14% O2, 10% O2, 10% O2 + 3% CO2, and 10% O2 + 5% CO2) and instrumented for recording of renal nerve activity. After a 30-min control period, rabbits were subjected to one of the four gas mixtures for 30 min, and then room air was resumed for a further 30 min. The four gas mixtures increased renal SNA by 14, 38, 49, and 165% respectively, but arterial pressure (thus renal perfusion pressure) was not altered by any of the gas mixtures. The greatest level of sympathetic activation produced significant falls in glomerular filtration rate (GFR), renal blood flow, sodium and fluid excretion, and significant increases in plasma renin activity. These returned to levels not significantly different from control conditions in the 30-min period after the gas mixture. When the changes to the various gas mixtures were analyzed within each rabbit, a significant linear relationship was found with all variables to the increase in SNA. Renal denervation in a separate group of seven rabbits completely abolished all of the above responses to the different gas mixtures. Thus graded activation of renal nerves induced by changes in inspired gas mixtures resulted in graded decreases in renal blood flow, GFR, and sodium excretion and graded increases in renin activity, with the changes occurring across a similar range of nerve activities; there was no evidence for a selective change in any renal variable.

Neurogenic regulation of proximal bicarbonate and chloride reabsorption

1986 ◽  
Vol 250 (1) ◽  
pp. F22-F26 ◽  
Author(s):  
M. G. Cogan
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Sprague Dawley ◽  
Electrolyte Excretion ◽  
Nerve Activity ◽  
Renal Nerve ◽  
Single Nephron ◽  
Renal Nerve Activity ◽  
Chloride Excretion

Although a change in renal nerve activity is known to alter proximal reabsorption, it is unclear whether reabsorption of NaHCO3 or NaCl or both are affected. Sprague-Dawley rats (n = 10) were studied using free-flow micropuncture techniques during euvolemia and following acute ipsilateral denervation. Glomerular filtration rate and single nephron glomerular filtration rate were stable. Absolute proximal bicarbonate reabsorption fell following denervation (933 +/- 40 to 817 +/- 30 pmol/min) with a parallel reduction in chloride reabsorption (1,643 +/- 116 to 1,341 +/- 129 peq/min). Urinary sodium, potassium, bicarbonate, and chloride excretion all increased significantly. To further assess the physiological significance of neurogenic modulation of proximal transport, other rats (n = 6) were subjected to acute unilateral nephrectomy (AUN). There is evidence that AUN induces a contralateral natriuresis (renorenal reflex) at least partially by causing inhibition of efferent renal nerve traffic. AUN caused significant changes in proximal NaHCO3 and NaCl reabsorption as well as in whole kidney electrolyte excretion in the same pattern as had denervation. Prior denervation of the remaining kidney prevented the proximal and whole kidney response to AUN (n = 6). In conclusion, depression of renal nerve activity inhibits both NaHCO3 and NaCl reabsorption in the rat superficial proximal convoluted tubule. The data are consistent with the hypothesis that changes in renal nerve activity modify whole kidney electrolyte excretion under physiological conditions at least partially by regulating proximal transport.

Renal nerves and cation excretion after acute reduction in functioning renal mass in the rat

1984 ◽  
Vol 246 (3) ◽  
pp. F260-F265 ◽  
Author(s):  
J. Ribstein ◽  
M. H. Humphreys
Keyword(s):  
Glomerular Filtration Rate ◽  
Mean Arterial Pressure ◽  
Renal Mass ◽  
Filtration Rate ◽  
Renal Nerves ◽  
Potassium Excretion ◽  
Contralateral Kidney ◽  
Efferent Limb ◽  
Ureteral Occlusion

We evaluated the role of the renal nerves in the increased cation excretion by the contralateral kidney after acute unilateral nephrectomy (AUN) or unilateral ureteral occlusion (UUO) in anesthetized rats. Both AUN and UUO caused large increases in sodium (UNaV) and potassium excretion (UKV) by the control kidney without change in glomerular filtration rate or mean arterial pressure. Prior denervation of either the ipsilateral (experimental) kidney or the control kidney completely prevented the increase in UNaV and UKV after UUO. Prior denervation of either kidney also prevented the increase in UNaV after AUN. However, a significant kaliuresis persisted after AUN despite unilateral denervation although reduced in magnitude when compared with the increase in UKV after AUN with both kidneys innervated. These results indicate that the renal nerves play a major role in the excretory response of the control kidney after acute reduction in functioning renal mass. This role of the renal nerves may be through the activation of a renorenal reflex. The reflex is activated by afferents from the ipsilateral kidney; the efferent limb is composed of the renal nerves to the control kidney. This reflex can entirely account for the compensatory increase in cation excretion after UUO. However, a separate mechanism, not dependent on the renal nerves, contributes to UKV after AUN.

Age-dependent changes in afferent renal nerve activity in genetically hypertensive rats

1992 ◽  
Vol 262 (5) ◽  
pp. R834-R841 ◽  
Author(s):  
N. G. Moss ◽  
A. B. Scoltock
Keyword(s):  
Single Unit ◽  
Renal Ischemia ◽  
Renal Nerves ◽  
Hypertensive Rats ◽  
Nerve Activity ◽  
Renal Nerve ◽  
Wky Rats ◽  
Renal Nerve Activity ◽  
Single Unit Recordings ◽  
Wistar Kyoto

Multiunit and single-unit recordings of afferent renal nerve activity (ARNA) were obtained in anesthetized spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats between 35 and 150 days of age. Intrapelvic backflow of urine at 20 mmHg excited ARNA at all ages in SHR (152 +/- 18% above control) and WKY rats (262 +/- 24%). In SHR, complete renal ischemia was more excitatory in rats older than 120 days (1,233 +/- 103%, n = 8) than in younger SHR (317 +/- 28%, n = 42). Single-unit recordings showed that this was related to the appearance of R1 chemoreceptors in older SHR and coincided with a decline in the proportion of R2 chemoreceptors in the renal nerves. Other chemoreceptive responses were identified in single units that did not show complete R1 or R2 characteristics, some of which showed responses consistent with a transformation process from R2 to R1 receptor type. R1 chemoreceptors were not present in WKY rats studied up to 150 days of age and, unlike SHR, the proportion of R2 chemoreceptors did not decline with age. Accordingly, complete renal ischemia in WKY rats caused a comparable excitation in multiunit ARNA at all ages (285 +/- 33%, n = 43). Oral enalapril from weaning to 100 days of age prevented hypertension in SHR but did not impair the responsiveness of ARNA to any stimulus. In WKY rats, enalapril treatment for the same period resulted in exaggerated ARNA response to renal ischemia (1,250 +/- 377% above control).(ABSTRACT TRUNCATED AT 250 WORDS)

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