Renal Vascular Response to Haemorrhage in the Rabbit after Pentobarbitone, Chloralose–Urethane and Ether Anaesthesia

1978 ◽  
Vol 54 (5) ◽  
pp. 489-494
Author(s):  
D. J. Warren ◽  
J. G. G. Ledingham
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Renal Cortex ◽  
Ether Anaesthesia ◽  
Before And After ◽  
Conscious Rabbits ◽  
Urethane Anaesthesia ◽  
Renal Vascular ◽  
Cortical Distribution ◽  
Total Renal Blood Flow

1. Total renal blood flow and its cortical distribution were measured by the microsphere technique before and after haemorrhage in conscious rabbits, and after haemorrhage in rabbits anaesthetized with pentobarbitone, chloralose—urethane or ether. 2. The average blood loss necessary to achieve a fall in systolic blood pressure to about 65 mmHg was 101 ml in conscious rabbits and 38, 90 and 118 ml in weight-matched groups of rabbits anaesthetized with pentobarbitone, chloralose—urethane and ether respectively. 3. After haemorrhage in conscious rabbits total renal blood flow fell by 25%, this fall being confined to the superficial renal cortex. 4. In rabbits subject to haemorrhage under pentobarbitone anaesthesia renal blood flow fell by a further 23% when compared with the conscious bled rabbits. This reduction in blood flow was confined to the superficial cortex. 5. Haemorrhage in the rabbits subjected to chloralose—urethane anaesthesia caused no significant change in renal blood flow, as compared with conscious bled rabbits. 6. Haemorrhage under ether anaesthesia was associated with a further 33% fall in total renal blood flow, as compared with conscious bled rabbits. This was associated with a fall of 32% and 34% in superficial and deep cortical blood flow respectively. 7. Animals subjected to general anaesthesia may be particularly susceptible to the renal haemodynamic effects of haemorrhage.

Renal Circulatory Responses to General Anaesthesia in the Rabbit: Studies Using Radioactive Microspheres

1975 ◽  
Vol 48 (1) ◽  
pp. 61-66 ◽  
Author(s):  
D. J. Warren ◽  
J. G. G. Ledingham
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Sodium Excretion ◽  
Urinary Sodium Excretion ◽  
Control Mechanisms ◽  
Anaesthetic Agents ◽  
Regional Renal Blood Flow ◽  
Urethane Anaesthesia ◽  
Cortical Distribution ◽  
Total Renal Blood Flow

1. Total renal blood flow and its cortical distribution were measured by the radioactive microsphere technique in conscious rabbits and after anaesthesia with pentobarbitone, chloralose-urethane or ether. 2. Pentobarbitone anaesthesia caused a fall of 26% in total renal blood flow, of 26% in superficial cortical flow, and of 24% in deep cortical flow. Sodium excretion rate fell by 33%. 3. Chloralose-urethane anaesthesia caused no change in total or regional renal blood flow, or in sodium excretion. 4. Ether anaesthesia caused an insignificant fall in total renal blood flow, but superficial cortical flow fell by 13 % and deep cortical flow rose by 21 %. Urinary sodium excretion fell by 65%. 5. Possible mechanisms for these changes in response to anaesthesia are discussed. 6. The effects of anaesthetic agents may influence the interpretation of published work on control mechanisms in the renal circulation.

Measurement of Intrarenal Blood-Flow Distribution in the Rabbit Using Radioactive Microspheres

1975 ◽  
Vol 48 (1) ◽  
pp. 51-60 ◽  
Author(s):  
D. J. Warren ◽  
J. G. G. Ledingham
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Renal Cortex ◽  
Flow Distribution ◽  
Rabbit Kidney ◽  
Radioactive Microspheres ◽  
Injection Dose ◽  
Intrarenal Blood Flow ◽  
Total Renal Blood Flow

1. Total renal blood flow and its distribution within the renal cortex of the conscious rabbit were studied with radioactive microspheres of 15 and 25 μm diameter. 2. The reliability of the microsphere technique was influenced by microsphere diameter and number (dose). The optimum microsphere diameter for determination of flow distribution in the rabbit kidney was 15 μm and dose 100–150 000 spheres. 3. Spheres of 15 μm nominal diameter were randomly distributed within the renal cortex of adult rabbits. The larger spheres in batches nominally 15 μm in diameter in young rabbits and 25 μm diameter in adult rabbits were preferentially distributed to the superficial cortex. 4. In adult rabbits 15 μm diameter spheres lodged in glomerular capillaries. Larger spheres occasionally lodged in interlobular arteries causing intrarenal haemorrhage. 5. Microspheres of 15 μm caused a decrease in renal clearance of creatinine and of p-aminohippurate when the total injection dose was about 200 000 spheres. These effects were greater when the injection dose was increased to 500 000 spheres. 6. The reduction in total renal blood flow observed with large doses of spheres largely reflected decreased outer cortical flow, as measured by a second injection of spheres, and confirmed by a decrease in p-aminohippurate extraction. 7. The reproducibility of multiple injection studies was limited by these intrarenal effects of microspheres. 8. Total renal blood flow measured in six rabbits in acute experiments by the microsphere technique was 107 ± 12 (mean±sd) ml/min and by p-aminohippurate clearance was 100 ± 10 ml/min. 9. Total renal blood flow in twelve conscious, chronically instrumented rabbits was 125 ± 11 ml/min, of which 92 ± 6 ml/min was distributed to the superficial cortex and 33 ± 4 ml/min to the deep cortex.

Alteration of canine renal vascular response to hemorrhage by inhibitors of prostaglandin synthesis

1976 ◽  
Vol 230 (4) ◽  
pp. 940-945 ◽  
Author(s):  
JL Data ◽  
LC Chang ◽  
AS Nies
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Control Period ◽  
Prostaglandin Synthesis ◽  
Hemorrhagic Hypotension ◽  
Renal Cortical Blood Flow ◽  
Renal Vascular ◽  
Inner Cortex ◽  
Equal Thickness ◽  
Total Renal Blood Flow

The involvement of prostaglandins in the redistribution of renal cortical blood flow to inner cortical nephrons during hemorrhagic hypotension was studied in the pentobarbital-anesthetized dog. Total renal blood flow and distribution of renal cortical flow were determined with the radioactive microsphere technique by dividing the cortex into four zones of equal thickness, zone 1 being outermost and zone 4 being juxtamedullary. Two inhibitors of prostaglandin synthesis were used: indomethacin 8 mg/kg and aspirin 100 mg/kg. The inhibitor or the vehicle was given intravenously prior to a control period which was followed by a hemorrhage sufficient to decrease arterial pressure by about one-third. The distribution of cortical flow was determined before hemorrhage, during hemorrhagic hypotension, and after transfusion. In the vehicle-treated dogs, total renal blood flow was well maintained, but flow redistributed to favor the inner cortical nephrons. This vasodilation in the inner cortex was blocked by both inhibitors of prostaglandin synthesis resulting in a decrease in total renal blood flow and relative ischemia of the juxtamedullary nephrons. Salicylate levels required to accomplish blockage of inner cortical vasodilaton were less than 7 mg/100 ml. These studies indicate that prostaglandins are responsible for the decreased vascular resistance of the inner cortical nephrons which results in the redistribution of blood flow during hemorrhage, and when prostaglandin synthesis is blocked, the kidney vasculature constricts during hemorrhage.

Effects of Free Radical Scavengers on Renal Circulation after Ischaemia in the Rabbit

1983 ◽  
Vol 65 (6) ◽  
pp. 605-610 ◽  
Author(s):  
R. Hansson ◽  
O. Jonsson ◽  
S. Lundstam ◽  
S. Pettersson ◽  
T. Scherstén ◽  
...  
Keyword(s):  
Blood Flow ◽  
Superoxide Dismutase ◽  
Renal Blood Flow ◽  
Vascular Resistance ◽  
Renal Vascular Resistance ◽  
Free Radical Scavengers ◽  
Renal Circulation ◽  
Outer Stripe ◽  
Renal Vascular ◽  
Total Renal Blood Flow

1. The intrarenal erythrocyte distribution, total renal blood flow and renal vascular resistance were studied before and during recirculation after 60 min of warm ischaemia in three groups of rabbits. One group was pretreated with superoxide dismutase, another with catalase and the third group was not pretreated at all. 2. In non-pretreated ischaemic kidneys there was a significant trapping of labelled erythrocytes in the outer stripe of the medulla. This trapping was not seen in non-ischaemic control kidneys and was completely prevented by pretreatment with either superoxide dismutase or catalase. 3. In non-pretreated ischaemic kidneys there was a transient increase in total renal blood flow during the first 5 min of recirculation, after which it returned to preischaemic values. After pretreatment with catalase the postischaemic increase in blood flow was more pronounced but again the blood flow returned to preischaemic values within 30 min. Pretreatment with superoxide dismutase resulted in a rapid postischaemic increase in blood flow which remained high throughout the 30 min period studied. 4. The renal vascular resistance decreased initially during recirculation after ischaemia in both pretreated and non-pretreated kidneys. In the latter it returned to pre-ischaemic values within 10 min whereas a slower increase was observed after catalase pretreatment. After pretreatment with superoxide dismutase the resistance remained low during the 30 min recorded.

Inner medullary blood flow in postischemic acute renal failure in the rat

1989 ◽  
Vol 256 (3) ◽  
pp. F456-F461 ◽  
Author(s):  
Y. Yagil ◽  
M. Miyamoto ◽  
R. L. Jamison
Keyword(s):  
Blood Flow ◽  
Renal Artery ◽  
Renal Blood Flow ◽  
Vascular Resistance ◽  
Renal Ischemia ◽  
Renal Vascular Resistance ◽  
Left Renal Artery ◽  
Vasa Recta ◽  
Renal Vascular ◽  
Total Renal Blood Flow

To study the effect of renal ischemia on the circulation in the inner medulla, blood flow in descending and ascending vasa recta was determined by fluorescence videomicroscopy in the exposed papilla of the uninephrectomized rat after clamping of the renal artery for 45 min. Total renal blood flow was determined in parallel studies with an electromagnetic flowmeter. Animals were studied 90 min (group 1E) and 24 h (group 2E) after right nephrectomy and release of the left renal artery clamp. Control rats were studied 90 min (group 1C) and 24 h (group 2C) after right nephrectomy alone. In groups 1E and 2E, total renal blood flow was reduced to 70 and 80% of that in their respective controls; renal vascular resistance increased by 50 and 73%, respectively. In striking contrast, blood flow was markedly elevated in descending and ascending vasa recta in groups 1E and 2E compared with the values in their respective uninephrectomized controls. These results indicate that the circulation in the inner medulla is rapidly restored after 45 min of total renal ischemia and that vasa recta blood flow rises above normal after 90 min and 24 h, despite a reduction in total renal blood flow and an increase in renal vascular resistance.

Effect of Prostaglandin Inhibition on the Renal Vascular Response to Ionic and Non-Ionic Contrast Media in the Dog

1984 ◽  
Vol 25 (5) ◽  
pp. 407-410 ◽  
Author(s):  
G. Lund ◽  
S. Einzig ◽  
J. Rysavy ◽  
E. Salomonowitz ◽  
W. Castaneda-Zuniga ◽  
...  
Keyword(s):  
Blood Flow ◽  
Contrast Media ◽  
Contrast Medium ◽  
Renal Blood Flow ◽  
Vascular Response ◽  
Contrast Injection ◽  
Ionic Contrast ◽  
Before And After ◽  
Ionic Contrast Medium ◽  
Renal Vascular

In an attempt to study the role of prostaglandins in the renal vascular response to contrast media in mongrel dogs, renal arterial injections of 6 ml of either the non-ionic contrast medium Iopamidol or the ionic medium diatrizoate meglumine/Na+ were performed, before and after intravenous injection of a buffered solution of acetylsalicylic acid (10 mg/kg) (ASA). Renal blood flow was recorded using non-occluding electromagnetic flow probes. The resting renal blood flow was significantly reduced after ASA. The usual biphasic response to contrast injection was observed both before and after ASA, and using either contrast medium. Analysis of the results failed to show any difference in degree of vasodilation or vasoconstriction after ASA. We conclude that prostaglandins may affect the resting level of renal blood flow but are not mediators of the instantaneous changes in response to contrast injection.

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.

Human renal response to meat meal

1986 ◽  
Vol 250 (4) ◽  
pp. F613-F618 ◽  
Author(s):  
T. H. Hostetter
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Renal Plasma Flow ◽  
Statistical Significance ◽  
Prostaglandin E ◽  
Base Line ◽  
Meat Meal ◽  
Time Period ◽  
Beef Steak ◽  
Renal Vascular

Glomerular filtration rate (GFR) increases after a meat meal in several species. The mechanism of this phenomenon is unknown and the excretory and metabolic responses largely unexplored. We examined in humans the nature of the hemodynamic response to a meat meal, the role of salt and water load in this response, and the associated renal excretory responses. Ten normal volunteers were studied after eating an average of 3.5 g/kg body wt of lean cooked beef steak and, on a separate day, after ingesting an amount of sodium and water equivalent to that in the steak. Average GFR increased by 28% for the entire 3 h after the meat meal compared with the same time period after the control salt solution (90 +/- 8 vs. 114 +/- 6 ml X min-1 X 1.73 M-2, mean +/- SE, P less than 0.05) and by 15% compared with the base-line periods, although this difference was not of statistical significance. However, not all subjects demonstrated an increase, and in those eight who did the degree was variable from 5 to 46% for the 3-h mean above the basal value. During the hour of peak GFR, the increment was associated with a nearly proportional increase in renal plasma flow and renal blood flow (all P less than 0.05). The increase in renal blood flow was entirely due to a significant fall in renal vascular resistance. The vasodilation was not accompanied by any change in prostaglandin E excretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Contribution of renal nerves to renal blood flow variability during hemorrhage

1998 ◽  
Vol 274 (5) ◽  
pp. R1283-R1294 ◽  
Author(s):  
Simon C. Malpas ◽  
Roger G. Evans ◽  
Geoff A. Head ◽  
Elena V. Lukoshkova
Keyword(s):  
Blood Flow ◽  
Arterial Pressure ◽  
Renal Blood Flow ◽  
Spectral Power ◽  
Sympathetic Nerves ◽  
Renal Nerves ◽  
Similar Frequency ◽  
Blood Withdrawal ◽  
Conscious Rabbits ◽  
Renal Sympathetic

We have examined the role of the renal sympathetic nerves in the renal blood flow (RBF) response to hemorrhage in seven conscious rabbits. Hemorrhage was produced by blood withdrawal at 1.35 ml ⋅ min−1 ⋅ kg−1for 20 min while RBF and renal sympathetic nerve activity (RSNA) were simultaneously measured. Hemorrhage was associated with a gradual increase in RSNA and decrease in RBF from the 4th min. In seven denervated animals, the resting RBF before hemorrhage was significantly greater (48 ± 1 vs. 31 ± 1 ml/min intact), and the decrease in RBF did not occur until arterial pressure also began to fall (8th min); however, the overall percentage change in RBF by 20 min of blood withdrawal was similar. Spectral analysis was used to identify the nature of the oscillations in each variable. Before hemorrhage, a rhythm at ∼0.3 Hz was observed in RSNA, although not in RBF, whose spectrogram was composed mostly of lower-frequency (<0.25 Hz) components. The denervated group of rabbits had similar frequency spectrums for RBF before hemorrhage. RSNA played a role in dampening the effect of oscillations in arterial pressure on RBF as the transfer gain between mean arterial pressure (MAP) and RBF for frequencies >0.25 Hz was significantly less in intact than denervated rabbits (0.83 ± 0.12 vs. 1.19 ± 0.10 ml ⋅ min−1 ⋅ mmHg−1). Furthermore, the coherence between MAP and RBF was also significantly higher in denervated rabbits, suggesting tighter coupling between the two variables in the absence of RSNA. Before the onset of significant decreases in arterial pressure (up to 10 min), there was an increase in the strength of oscillations centered around 0.3 Hz in RSNA. These were accompanied by increases in the spectral power of RBF at the same frequency. As arterial pressure fell in both groups of animals, the dominant rhythm to emerge in RBF was centered between 0.15 and 0.20 Hz and was present in intact and denervated rabbits. It is speculated that this is myogenic in origin. We conclude that RSNA can induce oscillations in RBF at 0.3 Hz, plays a significant role in altering the effect of oscillations in arterial pressure on RBF, and mediates a proportion of renal vasoconstriction during hemorrhage in conscious rabbits.

scholarly journals Angiotensin 1-7 Administration Increases Renal Blood Flow in the Absence of Bradykinin B2 Receptor in Ovariectomized Estradiol Treated Rats: The Role of Mas Receptor

2019 ◽  
Author(s):  
Shadan Saberi ◽  
Aghdas Dehghani ◽  
Mehdi Nematbakhsh
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Ovariectomized Rats ◽  
Vehicle Group ◽  
Estradiol Valerate ◽  
Bradykinin B2 Receptor ◽  
Hoe 140 ◽  
Group 2 ◽  
Renal Vascular

Abstract- Renin angiotensin (RAS), kallikrein kinin (KKS), and sex hormonal systems demonstrate a complex contribution in kidney circulation. This study was designed to investigate the role of angiotensin 1-7 (Ang 1-7) receptor (MasR) and of bradykinin B2 receptor (B2R) in renal blood flow (RBF) response to Ang 1-7 infusion in ovariectomized estradiol treated rats. The ovariectomized rats received intramuscular vehicle (group 1, OV) or estradiol valerate (500 µg/Kg/week) (group 2, OVE) for two weeks. Then each group was divided into two subgroups subjected to receive B2R antagonist (HOE-140, subgroup A), or MasR antagonist (A779) plus HOE-140 (subgroup B). RBF and renal vascular resistance (RVR) responses to graded Ang 1-7 infusion were determined. In condition of B2R alone blocking, RBF response to Ang 1-7 in OVE group was significantly greater than that of OV group (P=0.05), however this response difference was failed by co-blockades of MasR and B2R. Estradiol could promote RBF response to graded Ang 1-7 infusion in the absence of B2R alone, however when both receptors (MasR and B2R) were blocked the role of estradiol was limited.

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