Efferent renal sympathetic nerve stimulation in vivo. Effects on regional renal haemodynamics in the Wistar rat, studied by laser‐Doppler technique

Rudenstam, J.; Bergström, Göran; Taghipour, K.; Göthberg, G; Karlström, Gunnar

doi:10.1111/j.1748-1716.1995.tb09922.x

Cited by 30 publications

(24 citation statements)

References 34 publications

(24 reference statements)

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“…In our present study, the RBF was maintained by bolus and continuous injections of ketamine, and these results are consistent with those of a previous report using conscious dogs [5]. It has been reported that ketamine increases arterial blood pressure and cardiac output [18]. The RBF may probably be maintained due to the increase in cardiac output.…”

Section: Discussionsupporting

confidence: 82%

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Effects of the Intravenously Administered Anaesthetics Ketamine, Propofol, and Thiamylal on the Cortical Renal Blood Flow in Rats

Shiga

Minami²,

Uezono³

et al. 2003

Pharmacology

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Intravenous anaesthetics such as ketamine, propofol, and thiamylal are widely used, although the direct effects of these anaesthetics on the renal blood flow (RBF) have not been well elucidated. In this study, we examined the effects of bolus and continuous administrations of ketamine, propofol, and thiamylal on cortical RBF and the effects of noradrenaline (NA) on RBF under continuous administration of these anaesthetics. We used laser Doppler flowmetry to measure the effects of bolus injection and continuous infusion of ketamine, propofol, and thiamylal on cortical RBF in male Wistar rats. We also examined the effects of the anaesthetics on mean arterial blood pressure (MAP) and heart rate (HR). Bolus injections of ketamine, propofol, or thiamylal (1–8 mg/kg each, n = 10) at clinically relevant concentrations did not affect MAP, HR, or RBF. Continuous administration of ketamine, propofol, or thiamylal (1–8 mg/kg/h each, n = 10) did not affect MAP, HR or RBF. Exogenous NA (2 µg/kg) caused an increase in MAP and a decrease in RBF and HR. In experiments with continuous infusions of propofol or thiamylal (1–8 mg/kg/h each, n = 10), similar results were observed without infusion of any anaesthetics. However, bolus injection of NA did not result in a decrease in RBF during continuous ketamine infusion (98.8 ± 6.7% of control, n = 6, p < 0.05), while ketamine did not affect the NA-induced increase in MAP. In conclusion, bolus and continuous administrations of ketamine, propofol, and thiamylal did not affect the RBF. From our present findings, ketamine would be useful for maintaining the RBF.

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Section: Discussionsupporting

confidence: 82%

“…Superficial renocortical blood flow and total RBF are closely regulated by changes in vessel tone caused by the renal sympathetic nervous system [18]. Propofol is reported to reduce arterial blood pressure and cardiac output through direct vasodilation and through inhibition of the sympathetic nervous system [19,20].…”

Section: Discussionmentioning

confidence: 99%

Effects of the Intravenously Administered Anaesthetics Ketamine, Propofol, and Thiamylal on the Cortical Renal Blood Flow in Rats

Shiga

Minami²,

Uezono³

et al. 2003

Pharmacology

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“…Taken together, the results of these previous studies suggest that, compared with CBF (or total RBF), perfusion of the outer medulla is similarly sensitive (1), perfusion of the inner medulla is less sensitive (19,20), and perfusion at the tip of the papilla is almost completely insensitive (28), to the effects of neural activation. That is, given the caveat that these experiments were performed in different species and under different experimental conditions, they provide indirect evidence supporting the hypothesis that a gradient of sensitivity to neural stimulation exists from the outer medulla to papillary tip.…”

Section: Discussionmentioning

confidence: 55%

“…More recent studies have used more valid methods, such as local hydrogen gas clearance (1) and laserDoppler flowmetry (17-20, 28), but which provided data from only small anatomic regions in the outer medulla (1), inner medulla (17-20), and papillary tip (28). Taken together, the results of these previous studies suggest that, compared with CBF (or total RBF), perfusion of the outer medulla is similarly sensitive (1), perfusion of the inner medulla is less sensitive (19,20), and perfusion at the tip of the papilla is almost completely insensitive (28), to the effects of neural activation.…”

Section: Discussionmentioning

confidence: 99%

Regional responsiveness of renal perfusion to activation of the renal nerves

Guild

Eppel

Malpas

et al. 2002

American Journal of Physiology-Regulatory, Integrative and Comp

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We tested for regional differences in perfusion responses, within the renal medulla and cortex, to renal nerve stimulation in pentobarbital sodium-anesthetized rabbits. Laser-Doppler flux (LDF) was monitored at various depths below the cortical surface (1–15 mm). Basal cortical LDF (1–3 mm, ∼200–450 U) was greater than medullary LDF (5–15 mm, ∼70–160 U), but there were no statistically significant differences in basal LDF within these regions. The background LDF signal during aortic occlusion was similar in the cortex (2 mm, 31 U) and outer medulla (7 mm, 31 U), but slightly greater in the inner medulla (12 mm, 44 U). During electrical stimulation of the renal nerves (0.5–8 Hz), cortical LDF and total renal blood flow were similarly progressively reduced with increasing stimulus frequency. Medullary LDF (measured between 5 and 15 mm) was overall less responsive than cortical LDF. For example, 4-Hz stimulation reduced inner medullary LDF (9 mm) by 19 ± 6% but reduced cortical LDF (1 mm) by 54 ± 11%. However, medullary LDF responses to nerve stimulation were similar at all depths measured. Our results indicate that while the vascular elements controlling medullary perfusion are less sensitive to the effects of electrical stimulation of the renal nerves than are those controlling cortical perfusion, sensitivity within these vascular territories appears to be relatively homogeneous.

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“…Because of the similar degree of stenosis, basal renal hemodynamics and function were similarly decreased in RVD and RVDϩVitamins compared with controls. Medullary perfusion remained similar among the groups, likely as a renal defense mechanism to preserve the medulla and reflecting the independent regulation of medullary blood flow from that of the cortex (28,29).…”

Section: Discussionmentioning

confidence: 89%

Antioxidant Intervention Blunts Renal Injury in Experimental Renovascular Disease

Chade

Rodriguez-Porcel²,

Herrmann³

et al. 2004

Journal of the American Society of Nephrology

110

122

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Abstract. Atherosclerotic renovascular disease (RVD) amplifies damage in a stenotic kidney by inducing pro-inflammatory mechanisms and disrupting tissue remodeling. Oxidative stress is increased in RVD, but its direct contribution to renal injury has not been fully established. The authors hypothesized that chronic antioxidant intervention in RVD would improve renal function and attenuate tissue injury. Single-kidney hemodynamics and function at baseline and during vasoactive challenge were quantified using electron-beam computed tomography in pigs after 12 wk of experimental RVD (simulated by concurrent hypercholesterolemia and renal artery stenosis, n ϭ 7), RVD daily supplemented with antioxidant vitamins C (1 g), and E (100 IU/kg) (RVDϩVitamins, n ϭ 7), or controls (normal, n ϭ 7). Renal tissue was studied ex vivo using Western blot analysis and immunohistochemistry. Basal renal blood flow (RBF) and glomerular filtration rate (GFR) were similarly decreased in the stenotic kidney of both RVD groups. RBF and GFR response to acetylcholine was blunted in RVD, but significantly improved in RVDϩVitamins (P Ͻ 0.05 versus RVD). RVDϩVitamins also showed increased renal expression of endothelial nitric oxide synthase (eNOS) and decreased expression of NAD(P)H-oxidase, nitrotyrosine, inducible-NOS, and NF-B, suggesting decreased superoxide abundance and inflammation. Furthermore, decreased expression of pro-fibrotic factors in RVDϩVitamins was accompanied by augmented expression of extracellular (matrix metalloproteinase-2) and intracellular (ubiquitin) protein degradation systems, resulting in significantly attenuated glomerulosclerosis and renal fibrosis. In conclusion, chronic antioxidant intervention in early experimental RVD improved renal functional responses, enhanced tissue remodeling, and decreased structural injury. This study supports critical pathogenic contribution of increased oxidative stress to renal injury and scarring in RVD and suggests a role for antioxidant strategies in preserving the atherosclerotic and ischemic kidney.

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Efferent renal sympathetic nerve stimulation in vivo. Effects on regional renal haemodynamics in the Wistar rat, studied by laser‐Doppler technique

Cited by 30 publications

References 34 publications

Effects of the Intravenously Administered Anaesthetics Ketamine, Propofol, and Thiamylal on the Cortical Renal Blood Flow in Rats

Effects of the Intravenously Administered Anaesthetics Ketamine, Propofol, and Thiamylal on the Cortical Renal Blood Flow in Rats

Regional responsiveness of renal perfusion to activation of the renal nerves

Antioxidant Intervention Blunts Renal Injury in Experimental Renovascular Disease

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