A rapid bioassay for quantification of atrial natriuretic polypeptides

1987 ◽  
Vol 252 (5) ◽  
pp. R1009-R1014 ◽  
Author(s):  
K. Matsui ◽  
T. Kimura ◽  
K. Ota ◽  
M. Shoji ◽  
M. Inoue ◽  
...  
Keyword(s):  
Sodium Excretion ◽  
Urine Volume ◽  
Good Tool ◽  
Spontaneously Hypertensive ◽  
Assay Procedure ◽  
Rapid Bioassay ◽  
Wistar Kyoto ◽  
Dose Dependent ◽  
Atrial Natriuretic

A quantitative bioassay for the detection and quantification of atrial natriuretic polypeptides (ANPs) was developed in a pentobarbital-anesthetized rat. Ten percent mannitol in 0.9% saline was infused to achieve stable diuresis. The conductivity of the urine, urine flow, and blood pressure were continuously recorded. A bolus injection of synthetic alpha-human atrial natriuretic polypeptide (alpha-hANP) elicited dose-dependent increases in the urine conductivity, sodium excretion, and urine volume. Changes in the urine conductivity correlated significantly with the increase in sodium excretion. By use of changes in urine conductivity, biological ANP activity of crude rat atrial extract was determined. Atrial contents of ANP in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) were 25.5 +/- 1.2 microgram per atrium (n = 4) and 25.1 +/- 0.8 (n = 5) in euhydration. They were increased to 27.0 +/- 1.1 micrograms (n = 4) and 29.3 +/- 1.3 (n = 5, P less than 0.05), after 5-day water deprivation, respectively. This assay procedure provides a good tool for rapid and quantitative determination of ANPs.

Acute renal denervation produces a diuresis and natriuresis in young SHR but not WKY rats

1986 ◽  
Vol 251 (4) ◽  
pp. F655-F661 ◽  
Author(s):  
M. A. Rudd ◽  
R. S. Grippo ◽  
W. J. Arendshorst
Keyword(s):  
Sodium Excretion ◽  
Renal Denervation ◽  
Strain Differences ◽  
Urine Flow ◽  
Sprague Dawley ◽  
Renal Vasculature ◽  
Renal Nerve ◽  
Water Excretion ◽  
Spontaneously Hypertensive ◽  
Wistar Kyoto

Clearance experiments were conducted to determine the effect of acute unilateral renal denervation (DNX) on renal hemodynamics and salt and water excretion in anesthetized 6-wk-old spontaneously hypertensive rats (SHR) and Wistar-Kyoto genetic control rats (WKY). Before DNX, SHR had higher mean arterial pressure (33%) and renal vascular resistance (RVR) (57%) and lower glomerular filtration rate (GFR) (10%); urine flow and sodium excretion were similar. Following DNX in SHR, sodium and water excretion increased by 138 and 62%, respectively (P less than 0.001); GFR and RVR were unchanged. In contrast, DNX in WKY did not affect urine flow (0%) or sodium excretion (-21%). These strain differences were observed in Okamoto-Aoki rats from two sources. Effective DNX was indicated by 95% reduction of norepinephrine content 3 days after DNX in both strains. Six-week-old Sprague-Dawley and Munich-Wistar rats, in contrast to WKY, responded to DNX with a natriuresis (+182%) and diuresis (+95%) (P less than 0.001). Renal function was unaffected by sham DNX in SHR. Our results indicate that efferent renal nerve activity has little tonic influence on the renal vasculature in these young rats. Augmented neurotransmitter release and/or tubular responsiveness may be involved in fluid and electrolyte retention and the pathogenesis of hypertension in SHR. Conversely, blunted renal neuroeffector responses may prevent WKY from developing hypertension.

Atrial Natriuretic Peptide, Altitude and Acute Mountain Sickness

1989 ◽  
Vol 77 (5) ◽  
pp. 509-514 ◽  
Author(s):  
J. S. Milledge ◽  
J. M. Beeley ◽  
S. McArthur ◽  
A. H. Morice
Keyword(s):  
Body Weight ◽  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Packed Cell Volume ◽  
Sodium Excretion ◽  
Acute Mountain Sickness ◽  
Urine Volume ◽  
Symptom Scores ◽  
Mountain Sickness ◽  
Atrial Natriuretic

1. To investigate the mechanisms of acute mountain sickness, 22 subjects travelled to 3100 m by road and the following day walked to 4300 m on Mount Kenya. Control measurements were made over 2 days at 1300 m before ascent and for 2 days after arrival at 4300 m. These included body weight, 24 h urine volume, 24 h sodium and potassium excretion, blood haemoglobin, packed cell volume, and symptom score for acute mountain sickness. In 15 subjects blood samples were taken for assay of plasma aldosterone and atrial natriuretic peptide. 2. Altitude and the exercise in ascent resulted in a marked decrease in 24 h urine volume and sodium excretion. Aldosterone levels were elevated on the first day and atrial natriuretic peptide levels were higher on both altitude days compared with control. 3. Acute mountain sickness symptom scores showed a significant negative correlation with 24 h urinary sodium excretion on the first altitude day. Aldosterone levels tended to be lowest in subjects with low symptom scores and higher sodium excretion. No correlation was found between changes in haemoglobin concentration, packed cell volume, 24 h urine volume or body weight and acute mountain sickness symptom score. 4. Atrial natriuretic peptide levels at low altitude showed a significant inverse correlation with acute mountain sickness symptom scores on ascent.

Immunoreactive atrial natriuretic peptide in neuronal and glial cells of spontaneously hypertensive rat brain

1990 ◽  
Vol 258 (1) ◽  
pp. C109-C114 ◽  
Author(s):  
M. K. Raizada ◽  
B. Kimura ◽  
M. I. Phillips
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Glial Cells ◽  
Spontaneously Hypertensive Rat ◽  
Culture Media ◽  
Spontaneously Hypertensive ◽  
Glial Cultures ◽  
The Media ◽  
Wistar Kyoto ◽  
Atrial Natriuretic

Neuronal and glial cultures from the hypothalamic-brain stem areas of 1-day-old normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive (SH) rat brains stained positively with atrial natriuretic peptide (ANP)-specific antibodies. The endogenous levels of the ANP immunoreactivity in WKY neuronal and glial cultures were 17.0 +/- 2.2 and 14.3 +/- 2.7 pg/mg, respectively. Comparable neuronal and glial cultures from SH rat brains contained a 48 to 70% decrease in the endogenous ANP immunoreactivity levels. Culture media from both brain cell types also contained ANP immunoreactivity, the levels of which are significantly higher than those found in the cells. However, similar to endogenous levels, the media levels of immunoreactive ANP in SH neuronal and glial cultures were significantly reduced compared with WKY brain cultures. These observations demonstrate that endogenous ANP-like immunoreactivity is found in neuronal and glial cells and is released into the media. The levels of peptide are reduced in cultures of SH compared with WKY cultures, suggesting a genetically controlled difference between the hypertensive and normotensive rat strains long before hypertension develops.

scholarly journals Long-term exercise attenuates blood pressure responsiveness and modulates kidney angiotensin II signalling and urinary sodium excretion in SHR

2011 ◽  
Vol 12 (4) ◽  
pp. 394-403 ◽  
Author(s):  
Silmara Ciampone ◽  
Rafael Borges ◽  
Ize P de Lima ◽  
Flávia F Mesquita ◽  
Elizabeth C Cambiucci ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Exercise Training ◽  
Sodium Excretion ◽  
Urinary Sodium Excretion ◽  
Urinary Sodium ◽  
Receptor Expression ◽  
Spontaneously Hypertensive ◽  
Wistar Kyoto

Observations have been made regarding the effects of long-term exercise training on blood pressure, renal sodium handling and renal renin–angiotensin–aldosterone (RAS) intracellular pathways in conscious, trained Okamoto–Aoki spontaneously hypertensive rats (SHR) and Wistar Kyoto (WKy) normotensive rats, compared with appropriate age-matched sedentary SHR and WKy. To evaluate the influence of exercise training on renal function and RAS, receptors and intracellular angiotensin II (AngII) pathway compounds were used respectively, and lithium clearance and western blot methods were utilised. The current study demonstrated that increased blood pressure in SHR was blunted and significantly reduced by long-term swim training between the ages of 6 and 16 weeks. Additionally, the investigators observed an increased fractional urinary sodium excretion in trained SHR (SHRT) rats, compared with sedentary SHR (SHRS), despite a significantly decreased creatinine clearance (CCr). Furthermore, immunoblotting analysis demonstrated a decreased expression of AT1R in the entire kidney of TSHR rats, compared with SSHR. Conversely, the expression of the AT2R, in both sedentary and trained SHR, was unchanged. The present study may indicate that, in the kidney, long-term exercise exerts a modulating effect on AngII receptor expression. In fact, the present study indicates an association of increasing natriuresis, reciprocal changes in renal AngII receptors and intracellular pathway proteins with the fall in blood pressure levels observed in TSHR rats compared with age-matched SSHR rats.

Enhanced ANG II activity in anterior pituitary cell aggregates from hypertensive rats

1988 ◽  
Vol 255 (3) ◽  
pp. R407-R411
Author(s):  
W. Robberecht ◽  
C. Denef
Keyword(s):  
Defined Medium ◽  
Pituitary Cell ◽  
Pituitary Cells ◽  
Cell Aggregates ◽  
Ang Ii ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Wistar Kyoto ◽  
Dose Dependent ◽  
Perifusion System

Pituitary cell reaggregates from 14-day-old and adult spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) were cultured in serum-free, chemically defined medium supplemented with the thyroid hormone triiodothyronine and the glucocorticoid dexamethasone. After 1 wk in culture, aggregates were transferred into a perifusion system, and the effect of angiotensin II (ANG II) on prolactin (PRL) and growth hormone (GH) release was studied. In aggregates from adult SHR, ANG II displayed a significant and dose-dependent GH releasing activity, whereas a negligible effect or no effect was seen in aggregates from adult WKY. In contrast, no difference in the stimulation of PRL release by ANG II was found. To exclude the possibility that the enhanced GH responsiveness was secondary to longstanding hypertension, aggregates from animals in the prehypertensive stage were studied. Both the GH and PRL responses to ANG II were significantly higher in aggregates from 14-day-old SHR than in aggregates from 14-day-old WKY. These data indicate that abnormal GH and PRL responses to ANG II exist in pituitary cell aggregates from SHR long before hypertension develops. Because these differences were found in pituitary cells maintained in culture for 1 wk, they do not seem to be secondary to changes in brain regulation of pituitary function but rather are caused by factors intrinsic to the pituitary.

Cardiovascular and renal effects of gamma-MSH in spontaneously hypertensive and normotensive Wistar Kyoto rats

1992 ◽  
Vol 262 (1) ◽  
pp. R77-R84 ◽  
Author(s):  
X. Y. Sun ◽  
Q. P. Feng ◽  
Q. L. Gong ◽  
L. Edvinsson ◽  
T. Hedner
Keyword(s):  
Pressor Response ◽  
Urinary Sodium Excretion ◽  
Intrathecal Administration ◽  
Renal Effects ◽  
Spontaneously Hypertensive ◽  
Melanocyte Stimulating Hormone ◽  
Pithed Rats ◽  
Wistar Kyoto ◽  
Dose Dependent Increase ◽  
Dose Dependent

The objective of this study was to compare the cardiovascular and renal effects of the two gamma-melanocyte-stimulating hormone (MSH) peptide sequences in the pro-opiomelanocortin prohormone structure in conscious, anesthetized, and pithed spontaneous hypertensive rats (SHR) and normotensive Wistar Kyoto (WKY) controls. In the conscious but not in the pithed rats, intravenous injection of gamma 2- and gamma 1-MSH induced a rapid and dose-dependent increase in mean arterial pressure (MAP), and gamma 2-MSH was more potent than gamma 1-MSH. The pressor response was more pronounced and more sustained in the SHR compared with the WKY. There were dose-dependent and significant increases in heart rate (HR) after gamma 2- and gamma 1-MSH in the SHR. At intravenous infusions of low doses of gamma 2-MSH, which did not significantly influence MAP or HR, urinary sodium excretion was significantly increased in both SHR and WKY. In conscious, but not in anesthetized rats, intracerebroventricular administration of the gamma 2-MSH peptide induced sustained increases in MAP in both SHR and WKY. After intrathecal administration, there were transient pressor effects of gamma 2-MSH. We conclude that the pro-opiomelanocortin-derived gamma 2- and gamma 1-MSH peptide sequences possess potent rapid pressor actions. The pressor effects, which require an intact sympathetic nervous system, are more pronounced in the SHR strain. Moreover, gamma 2-MSH induces natriuresis when administered in nonpressor doses in WKY and SHR.

Impaired renal D1-like and D2-like dopamine receptor interaction in the spontaneously hypertensive rat

2001 ◽  
Vol 281 (4) ◽  
pp. R1071-R1078 ◽  
Author(s):  
Cecilia A. Ladines ◽  
Chunyu Zeng ◽  
Laureano D. Asico ◽  
Xiaoguang Sun ◽  
Felice Pocchiari ◽  
...  
Keyword(s):  
Dopamine Receptor ◽  
Sodium Excretion ◽  
Spontaneously Hypertensive Rat ◽  
Rank Order ◽  
Urine Flow ◽  
Receptor Interaction ◽  
Dopamine Receptor Agonist ◽  
Renal Tubules ◽  
Spontaneously Hypertensive ◽  
Wistar Kyoto

D1-like (D1, D5) and D2-like (D2, D3, D4) dopamine receptors interact in the kidney to produce a natriuresis and a diuresis. Disruption of D1 or D3 receptors in mice results in hypertension that is caused, in part, by a decreased ability to excrete an acute saline load. We studied D1-like and D2-like receptor interaction in anesthetized spontaneously hypertensive rats (SHR) by the intrarenal infusion of Z-1046 (a novel dopamine receptor agonist with rank order potency of D3≥D4>D2>D5>D1). Z-1046 increased glomerular filtration rate (GFR), urine flow, and sodium excretion in normotensive Wistar-Kyoto rats but not in SHRs. The lack of responsiveness to Z-1046 in SHRs was not an epiphenomenon, because intrarenal cholecystokinin infusion increased GFR, urine flow, and sodium excretion to a similar extent in the two rat strains. We conclude that renal D1-like and D2-like receptor interaction is impaired in SHRs. The impaired D1-like and D2-like receptor interaction in SHRs is not caused by alterations in the coding sequence of the D3 receptor, the D2-like receptor expressed in rat renal tubules that has been shown to be involved in sodium transport. Because the diuretic and natriuretic effects of D1-like receptors are, in part, caused by an interaction with D2-like receptors, it is possible that the decreased Z-1046 action in SHRs is secondary to the renal D1-like receptor dysfunction in this rat strain.

Atrial natriuretic factor: reduced cardiac content in cirrhotic rats with ascites

1986 ◽  
Vol 250 (4) ◽  
pp. F749-F752 ◽  
Author(s):  
W. Jimenez ◽  
A. Martinez-Pardo ◽  
V. Arroyo ◽  
J. Gaya ◽  
F. Rivera ◽  
...  
Keyword(s):  
Plasma Renin Activity ◽  
Sodium Excretion ◽  
Atrial Natriuretic Factor ◽  
Urine Volume ◽  
Plasma Renin ◽  
Renin Activity ◽  
Natriuretic Factor ◽  
Tissue Content ◽  
Atrial Natriuretic

The present study was designed to investigate whether cirrhosis with ascites is associated with altered tissue content of atrial natriuretic factor. Atrial extracts from 14 cirrhotic rats with ascites and increased plasma renin activity (PRA) (14.4 +/- 4.6 ng X ml-1 X h-1) and aldosterone concentration (148.3 +/- 17.3 ng/dl) and from 10 control rats (PRA, 3 +/- 0.5 ng X ml-1 X h-1; aldosterone, 34.7 +/- 3.7 ng/dl) were intravenously injected into anesthetized normovolemic rats. Only one extract was assayed in each bioassay rat. Atrial extracts from control rats increased diuresis and natriuresis 513 +/- 91 and 3,029 +/- 752%, respectively (means +/- SE). In contrast, atrial extracts from cirrhotic rats increased urine volume 199 +/- 49% (P less than 0.001) and sodium excretion 546 +/- 132% (P less than 0.001). These results strongly suggest that atrial content of atrial natriuretic factor is reduced in cirrhotic rats as compared with control animals.

Abstract 349: Gastrin and D1 Dopamine Receptor Interact to Induce Natriuresis and Diuresis

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Yue Chen ◽  
Laureano D. Asico ◽  
Shuo Zheng ◽  
Van Anthony M. Villar ◽  
Duofen He ◽  
...  
Keyword(s):  
Sodium Excretion ◽  
Receptor Interaction ◽  
Gastrointestinal Hormone ◽  
Hypertensive Rats ◽  
Membrane Expression ◽  
Spontaneously Hypertensive ◽  
R And D ◽  
Wky Rats ◽  
Wistar Kyoto ◽  
Stimulation Of

Oral NaCl produces a greater natriuresis and diuresis than the intravenous infusion of the same amount of NaCl. Gastrin is the major gastrointestinal hormone taken up by renal proximal tubule (RPT) cells. We hypothesized that renal gastrin and dopamine receptors interact to synergistically increase sodium excretion, an impaired interaction of which may be involved in the pathogenesis of hypertension. In Wistar-Kyoto (WKY) rats, infusion of gastrin induced natriuresis and diuresis, which was abrogated in the presence of a gastrin (CCK B R; CI-988) or D 1 -like receptor antagonist (SCH23390). Similarly, the natriuretic and diuretic effects of fenoldopam, a D 1 -like receptor agonist, were blocked by SCH23390, as well as by CI-988. However, the natriuretic effects of gastrin and fenoldopam were not observed in spontaneously hypertensive rats (SHRs). The gastrin/D 1 -like receptor interaction was also confirmed in RPT cells. In RPT cells from WKY but not SHRs, stimulation of either D 1 -like or gastrin receptor inhibited Na + -K + -ATPase activity, an effect that was blocked in the presence of SCH23390 or CI-988. In RPT cells from WKY and SHRs, CCK B R and D 1 receptor (D 1 R) co-immunoprecipitated, which was increased after stimulation of either D 1 R or CCK B R in RPT cells from WKY rats; stimulation of one receptor increased RPT cell membrane expression of the other receptor, effects that were not observed in SHRs. These data suggest that there is a synergism between CCK B R and D 1 -like receptors to increase sodium excretion. An aberrant interaction between the renal CCK B R and D 1 -like receptors (e.g., D 1 R) may play a role in the pathogenesis of hypertension.

Characterization of renal aldosterone receptors in genetically hypertensive rats

1993 ◽  
Vol 264 (2) ◽  
pp. F286-F291 ◽  
Author(s):  
M. Horiuchi ◽  
H. Nishiyama ◽  
J. Hama ◽  
T. Takenaka ◽  
H. Kondo ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Urine Volume ◽  
Plasma Aldosterone ◽  
Type I ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Receptor Complexes ◽  
Genetically Hypertensive Rats ◽  
Wistar Kyoto ◽  
Genetically Hypertensive

To investigate the aldosterone responsiveness of genetically hypertensive rats, we compared characteristics of renal cytosolic aldosterone receptors from the M strain of stroke-prone, spontaneously hypertensive rats (M-SHRSP) with normotensive Wistar-Kyoto rats (WKY). In M-SHRSP, blood pressure was elevated significantly at 6 wk of age, when their plasma aldosterone concentrations were similar to those in WKY. Decreases in urine volume and sodium excretion were also observed in M-SHRSP. At 10 wk of age, M-SHRSP plasma aldosterone concentrations became significantly higher than those in WKY. On the other hand, the concentration of renal cytosolic aldosterone receptors (type I, aldosterone specific) had already increased at 6 wk of age in M-SHRSP, with no difference in affinity, and levels remained increased thereafter. There were no significant differences in molecular weights or ionic charges of either "activated" or "non-activated" aldosterone-receptor complexes between M-SHRSP and WKY, indicating that the molecular properties were similar in both groups. These results suggest that the increased concentration of aldosterone receptors in the kidneys of M-SHRSP might increase their aldosterone responsiveness and contribute to the development of high blood pressure in these animals.

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