Sclerocarya birrea [(A. Rich.) Hochst.] [Anacardiaceae] stem-bark ethanolic extract (SBE) modulates blood glucose, glomerular filtration rate (GFR) and mean arterial blood pressure (MAP) of STZ-induced diabetic rats

1. The effects of acute systemic α1-anoceptor blockade by doxazosin on glomerular filtration rate, urine flow, sodium clearance and lithium clearance were investigated in acutely prepared conscious rats. 2. Clearance experiments were performed during water diuresis (20 mmol/l NaCl and 110 mmol/l glucose, 3 ml/h). After a control period, animals were randomized to one of the following treatments: time-control (n = 9), doxazosin (50 μg primer; 30 μg h−1 kg−1) (n = 10), amiloride (1 mg primer; 2.4 mg h−1 kg−1) (n = 10) and doxazosin plus amiloride (n = 9). 3. Doxazosin reduced the mean arterial blood pressure from 125 to 108 mmHg; this was associated with transient reductions in glomerular filtration rate, urine flow and lithium clearance. After the transient anti-diuresis, the sodium excretion rate remained reduced in doxazosin-infused animals. Amiloride increased the sodium excretion rate without having effects on other variables. When doxazosin was given together with amiloride, the reduction in lithium clearance observed during the transient reduction in glomerular filtration rate and urine flow, was partly abolished. Thus the fractional lithium excretion was transiently increased in rats given doxazosin plus amiloride (from 29 to 40%), whereas in rats given doxazosin alone a non-significant reduction was observed (from 28 to 25%). The dissociation between lithium clearance and fractional lithium excretion in the two doxazosin-infused groups was only significant during the transient reduction in glomerular filtration rate and urine flow. 4. The results provide evidence for an amiloride-sensitive lithium reabsorption during acute systemic α1-adrenoceptor blockade. It is suggested that activation of baroreflexes during the acute reduction in mean arterial blood pressure is responsible for stimulation of distal lithium reabsorption by an unknown mechanism.

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Intraruminal rehydration of ovine fetuses

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1991.261.6.r1381 ◽

1991 ◽

Vol 261 (6) ◽

pp. R1381-R1387

Author(s):

M. G. Ross ◽

D. J. Sherman ◽

M. G. Ervin ◽

L. Day

Keyword(s):

Blood Pressure ◽

Glomerular Filtration Rate ◽

Filtration Rate ◽

Plasma Osmolality ◽

Urine Osmolality ◽

Distilled Water ◽

Intravascular Volume ◽

Fetal Plasma ◽

Arterial Blood ◽

Arterial Po2

During oral rehydration of adult mammals, oropharyngeal stimulation, the act of swallowing, and/or gastric factors contribute to a rapid decrease in plasma arginine vasopressin (AVP) that precedes plasma osmolality changes. To determine whether similar mechanisms are present in the developing fetus, six chronically prepared ovine fetuses were rehydrated with intraruminal (IR) distilled water infusions (1 ml.kg-1.min-1 for 60 min) after 43 +/- 3 h of maternal water deprivation. In response to maternal dehydration, significant increases were noted in maternal and fetal mean plasma osmolalities, sodium and AVP concentrations, and fetal urine osmolality. As estimated by hematocrit, fetal intravascular volume decreased by 11%. Fetal rehydration via IR distilled water infusion evoked a significant decrease in fetal plasma osmolality but no change in urine osmolality. Unexpectedly, fetal arterial blood pressure increased and arterial PO2 decreased while fetal hematocrit indicated a further 7% decrease in intravascular volume after the IR infusion. There was a nonsignificant trend toward increased fetal glomerular filtration rate, urine volume, and plasma AVP concentrations. Identical IR water infusions to five euhydrated fetuses resulted in significant decreases in fetal plasma osmolality and increases in glomerular filtration rate, urine flow, and osmolar excretion. The euhydrated fetuses also exhibited significant increases in mean arterial blood pressure and hematocrit and decreased fetal arterial PO2. These results indicate that IR water does not suppress AVP secretion in the dehydrated ovine fetus. Rather, both euhydrated and dehydrated fetuses exhibit an idiosyncratic vasoconstrictive response to IR water.

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The giraffe kidney tolerates high arterial blood pressure by high renal interstitial pressure and low glomerular filtration rate

Acta Physiologica ◽

10.1111/apha.12531 ◽

2015 ◽

Vol 214 (4) ◽

pp. 497-510 ◽

Cited By ~ 10

Author(s):

M. Damkjaer ◽

T. Wang ◽

E. Brøndum ◽

K. H. Østergaard ◽

U. Baandrup ◽

...

Keyword(s):

Blood Pressure ◽

Glomerular Filtration Rate ◽

Glomerular Filtration ◽

Arterial Blood Pressure ◽

Filtration Rate ◽

Interstitial Pressure ◽

Arterial Blood

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Endothelin-induced natriuresis and diuresis are pressure-dependent events in the rat

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1993.265.1.r90 ◽

1993 ◽

Vol 265 (1) ◽

pp. R90-R96 ◽

Cited By ~ 1

Author(s):

K. Uzuner ◽

R. O. Banks

Keyword(s):

Blood Pressure ◽

Glomerular Filtration Rate ◽

Arterial Pressure ◽

Filtration Rate ◽

Urine Flow ◽

Female Rats ◽

Arterial Blood ◽

Site Of Action ◽

Baseline Values ◽

The Right

The goal of the current study was to determine the mechanism by which doses of endothelin (ET) that do not markedly affect the glomerular filtration rate (GFR) cause a natriuresis and diuresis. ET was infused into pentobarbital-anesthetized female rats at 50 ng.kg-1.min-1 iv for 30 min. In controls (n = 6 rats; n = 5 in all other groups), ET increased mean arterial blood pressure (MAP) from 95 +/- 2 to 131 +/- 2 (SE) mmHg, Na excretion (UNa V) from 0.34 +/- 0.07 to 1.83 +/- 0.2 meq/min, and urine flow rate (V) from 13 +/- 1 to 24 +/- 3 ml/min (all P < 0.01 vs. baseline). At 15 min during infusion of ET, the GFR was not affected (2.1 +/- 0.1 to 2.2 +/- 0.1 ml/min) but modestly decreased to 1.8 +/- 0.1 ml/min at 30 min (P < 0.05 vs. baseline). Either removing the capsule from both kidneys during surgery or maintaining renal arterial pressure at baseline values with an adjustable clamp on the aorta above the right renal artery abolished the ET-induced increase in UNa V and V. Meclofenamate also did not alter the ET-induced increase in MAP, V, or UNa V. To determine the intrarenal site of action of ET, experiments were conducted with ET plus amiloride or with a combination of amiloride plus furosemide; there was a larger ET-induced diuresis and natriuresis in amiloride-treated rats and an even larger response with amiloride plus furosemide compared with controls.(ABSTRACT TRUNCATED AT 250 WORDS)

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Abstract 386: A Novel Aquaretic and Glomerular Filtration Rate Enhancing Peptide Without Vascular Vasodilatory Actions in Experimental CHF.

Circulation ◽

10.1161/circ.116.suppl_16.ii_61-b ◽

2007 ◽

Vol 116 (suppl_16) ◽

Author(s):

Horng H Chen ◽

ShuChong Pan ◽

John C Burnett ◽

Robert D Simari

Keyword(s):

Blood Pressure ◽

Amino Acids ◽

Glomerular Filtration Rate ◽

Glomerular Filtration ◽

Filtration Rate ◽

Urinary Sodium Excretion ◽

Sodium Concentration ◽

Water Excretion ◽

Arterial Blood ◽

Change In Mean

BACKGROUND: BNP is a cardiac peptide with vasodilatory, natriuretic and diuretic properties. Recent studies have suggested that its vasodilatory hypotensive properties may limit the renal actions of BNP, especially in patients with borderline low blood pressure. We have recently identified an alternatively spliced transcript for BNP (ASBNP) that includes a unique and distinct longer carboxyl-terminus consisting of 34 amino acids. Based upon preliminary studies, we generated a truncated form (ASBNP2.1) that contains the first 16 amino acids of the C-terminal of ASBNP. METHODS: We determined the cardiorenal and humoral actions of intravenous infusion of ASBNP2.1 at 2 pmol/Kg/min, 10 pmol/Kg/min and 100 pmol/Kg /min in 10 dogs with rapid ventricular pacing induced overt CHF (240 bpm for 10 days). * p<0.05 RESULTS: IV infusion of ASBNP 2.1 increased aquaresis (from 0.19±0.04 to 0.32±0.07, 0.46±0.11 and 0.39±0.09 ml/min*) without a significant change in urinary sodium excretion. Importantly, ASBNP 2.1 enhanced glomerular filtration rate (GFR), from 31±4 to 47±8, 69±10 and 56±9 ml/min*. These renal actions were associated with increases in urinary BNP*, ANP* and cGMP* excretion. BNP 2.1 did not have any systemic vasodilatory action resulting in no change in mean arterial blood pressure or cardiac-filling pressures even at the highest dose. There was not change in serum sodium concentration. CONCLUSION: We report for the first time that this novel peptide based upon ASBNP has potent aquaretic and GFR enhancing actions without the vasodilatory hypotensive properties in an experimental model of overt CHF. The lack of vasodilatation but with renal actions also suggest that the C-terminus plays a key role in the vascular actions of this peptide offering new insights into vascular-renal structure function of BNP and related peptides. This renal specific peptide may have potential therapeutic benefit in states of renal dysfunction with volume overload to enhance GFR and water excretion without the detrimental side effect of hypotension.

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Effect of inhibition of MAO and COMT on intrarenal dopamine and serotonin and on renal function

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.2001.280.1.r248 ◽

2001 ◽

Vol 280 (1) ◽

pp. R248-R254 ◽

Cited By ~ 22

Author(s):

Yongqing Wang ◽

Theresa J. Berndt ◽

Jennifer M. Gross ◽

Michael A. Peterson ◽

Mathew J. So ◽

...

Keyword(s):

Blood Pressure ◽

Renal Function ◽

Glomerular Filtration Rate ◽

Monoamine Oxidase ◽

Filtration Rate ◽

Interstitial Fluid ◽

Fractional Excretion ◽

Urine Flow ◽

Arterial Blood ◽

Fractional Excretion Of Sodium

The purpose of the present investigation was to study the effects of inhibition of monoamine oxidase (MAO) and/or catechol- O-methyltransferase (COMT), enzymes involved in the degradation of dopamine (DA) and serotonin (5-HT), on intrarenal DA and 5-HT, as reflected in the renal interstitial fluid (RIF) microdialysate and urine, and on renal function. Inhibition of MAO selectively increased RIF 5-HT from 3.16 ± 0.38 to 8.03 ± 1.83 pg/min ( n = 7, P < 0.05), concomitant with decreases in mean arterial blood pressure and glomerular filtration rate (2.09 ± 0.18 to 1.57 ± 0.22 ml/min, n = 7, P < 0.05). Inhibition of COMT significantly increased RIF DA (3.47 ± 0.70 to 8.68 ± 1.96 pg/min, n = 9, P < 0.05), urinary DA (2.00 ± 0.16 to 2.76 ± 0.26 ng/min, n = 9, P < 0.05), and absolute excretion of sodium (6.42 ± 2.00 to 9.82 ± 1.62 μmol/min, n = 10, P < 0.05). Combined inhibition of MAO and COMT significantly increased RIF DA, urinary DA, and urinary 5-HT, which was accompanied with increases in urine flow rate, and absolute (3.03 ± 0.59 to 8.40 ± 1.61 μmol/min, n = 9, P < 0.01) and fractional excretion of sodium. We conclude that inhibition of MAO selectively increases RIF 5-HT. COMT appears to be more important than MAO in the metabolism of intrarenal DA. Physiological increases in intrarenal DA/5-HT induced by inhibition of their degrading enzymes are accompanied with significant alterations of renal function.

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Angiotensin-(1–7) in the ovine fetus

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.2001.280.2.r404 ◽

2001 ◽

Vol 280 (2) ◽

pp. R404-R409 ◽

Cited By ~ 11

Author(s):

Karen M. Moritz ◽

Duncan J. Campbell ◽

E. Marelyn Wintour

Keyword(s):

Blood Pressure ◽

Glomerular Filtration Rate ◽

Glomerular Filtration ◽

Flow Rate ◽

Filtration Rate ◽

Plasma Concentrations ◽

Urine Flow ◽

Urine Flow Rate ◽

Ang Ii ◽

Arterial Blood

In the adult animal, ANG-(1–7) may counterbalance some effects of ANG II. Its effects in the fetus are unknown. Basal ANG-(1–7), ANG I, ANG II, and renin concentrations were measured in plasma from ovine fetuses and their mothers ( n = 10) at 111 days of gestation. In the fetus, concentrations of ANG I, ANG-(1–7), and ANG II were 86 ± 21, 13 ± 2, and 14 ± 2 fmol/ml, respectively. In the ewe, concentrations of ANG I were significantly lower (20 ± 4 fmol/ml, P < 0.05) as were concentrations of ANG-(1–7) (2.9 ± 0.6 fmol/ml), whereas ANG II concentrations were not different (10 ± 1 fmol/ml). Plasma renin concentrations were higher in the fetus (4.8 ± 1.1 pmol ANG I · ml−1 · h−1) than in the ewe (0.9 ± 0.2 pmol · ml−1 · h−1, P < 0.05). Infusion of ANG-(1–7) (∼9 μg/h) for a 3-day period caused a significant increase in plasma concentrations of ANG-(1–7) reaching a maximum of 448 ± 146 fmol/ml on day 3 of infusion. Plasma levels of ANG I and II as well as renin were unchanged by the infusion. Urine flow rate, glomerular filtration rate, and fetal arterial blood pressure did not change and were not different than values in fetuses receiving a saline infusion for 3 days ( n = 5). However, the osmolality of amniotic and allantoic fluid was significantly higher in fetuses that received ANG-(1–7). Also, compared with the saline-infused animals, mRNA expression levels of renin, the AT1 receptor, and AT2 receptor were elevated in kidneys of fetuses that received infusions of ANG-(1–7). Infusion of an ANG-(1–7) antagonist {[d-Ala7]-ANG-(1–7), 20 μg/h} for 3 days had no effect on fetal blood pressure or renal function. In conclusion, although infusion of ANG-(1–7) did not affect fetal urine flow rate, glomerular filtration rate, or blood pressure, changes in fetal fluids and gene expression indicate that ANG-(1–7) may play a role in the fetal kidney.

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Peripheral Haemodynamics and Renal Function in Relation to the Menstrual Cycle

Clinical Science ◽

10.1042/cs0910163 ◽

1996 ◽

Vol 91 (2) ◽

pp. 163-168 ◽

Cited By ~ 35

Author(s):

E. Van Beek ◽

A. J. H. M. Houben ◽

P. N. Van Es ◽

C. Willekes ◽

E. C. C. M. Korten ◽

...

Keyword(s):

Blood Pressure ◽

Blood Flow ◽

Glomerular Filtration Rate ◽

Menstrual Cycle ◽

Glomerular Filtration ◽

Luteal Phase ◽

Filtration Rate ◽

Vascular Tone ◽

Vascular Relaxation ◽

Arterial Blood

1. The objective of this study was to investigate whether the luteal phase of the menstrual cycle differs from the follicular phase by the development of a state of general vascular relaxation. 2. Once in the follicular and once in the luteal phase of the menstrual cycle, we measured by non-invasive techniques: arterial blood pressure (by finger blood pressure measurements), vascular tone (by pulse-wave velocity and plethysmography), blood flow to skin (by laser-Doppler), blood flow to forearm (by plethysmography) and blood flow to kidneys (by para-aminohippurate clearance), and the glomerular filtration rate (by inulin clearance). The data points obtained in the luteal phase were compared with those in the follicular phase by non-parametric tests. 3. Arterial blood pressure, vascular tone and the blood flows to the forearm and kidneys were comparable in the two phases of the menstrual cycle. In contrast, the blood flow to the skin was consistently lower, and the glomerular filtration rate higher in the luteal phase of the menstrual cycle. 4. The results of the present study do not support our hypothesis of a general vascular relaxation in the luteal phase of the menstrual cycle. The lower skin flow in the luteal phase may be an adaptation needed to ensure the higher core temperature of 0.3–0.5°C in the luteal phase. The higher glomerular filtration rate was in most cases paralleled by a higher renal blood flow in the luteal phase. This suggests that the higher glomerular filtration rate is secondary to a selective vasorelaxation of the afferent renal arterioles.

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

The American Journal of Chinese Medicine ◽

10.1142/s0192415x89000292 ◽

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.

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Diabetic nephropathy in the nurse practice

Medsestra (Nurse) ◽

10.33920/med-05-2005-13 ◽

2020 ◽

pp. 77-81

Author(s):

Hedy Muradova ◽

Vsevolod Skvortsov

Keyword(s):

Blood Pressure ◽

Diabetic Nephropathy ◽

Glomerular Filtration Rate ◽

Glomerular Filtration ◽

Kidney Failure ◽

Filtration Rate ◽

Clinical Syndrome ◽

Progressive Decrease ◽

Arterial Blood ◽

Kidney Lesions

Diabetic nephropathy (DN) is a clinical syndrome characterized by kidney lesions and formation narrow or diffusion glomerulosclerosis, which later becomes kidney failure. It is manifested by persistent albuminuria (>300 mg/day or >200 μg/min), that is confirmed on at least 2 occasions 3–6 months apart, with a progressive decrease in glomerular filtration rate (GFR) and elevated arterial blood pressure (BP).

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