Control of renal medullary blood flow by vasopressin V1 and V2 receptors

1995 ◽  
Vol 269 (1) ◽  
pp. R193-R200 ◽  
Author(s):  
K. Nakanishi ◽  
D. L. Mattson ◽  
V. Gross ◽  
R. J. Roman ◽  
A. W. Cowley
Keyword(s):  
Blood Flow ◽  
Laser Doppler Flowmetry ◽  
Arginine Vasopressin ◽  
Laser Doppler ◽  
Receptor Stimulation ◽  
Doppler Flowmetry ◽  
Medullary Blood Flow ◽  
V2 Receptor ◽  
Renal Medullary Blood Flow ◽  
Interstitial Infusion

Experiments were performed in anesthetized renal-denervated rats to determine the contribution of renal medullary vasopressin V1 and V2 receptor stimulation in the regulation of renal medullary blood flow. Renal medullary interstitial infusion of the selective V1 agonist [Phe2,Ile3,Orn8]vasopressin (2 ng.kg-1.min-1) significantly decreased outer medullary blood flow by 15% and inner medullary blood flow by 35%, as measured with implanted optical fibers for laser-Doppler flowmetry. Medullary interstitial infusion of equimolar doses of arginine vasopressin (AVP) also decreased outer medullary blood flow by 15% but decreased inner medullary blood flow by only 17%, a decrease significantly less than that during the infusion of the V1 agonist. These results were confirmed in videomicroscopy experiments on the exposed papilla, which demonstrated that the V1 agonist and AVP decreased descending and ascending vasa recta capillary red blood cell velocity and calculated blood flow, with greater decreases during infusion of the V1 agonist. In further laser-Doppler flowmetry studies, stimulation of V2 receptors by medullary interstitial infusion of 1-desamino-8-D-arginine vasopressin (2 ng.kg-1.min-1) or AVP in rats pretreated with the vasopressin V1 receptor antagonist d(CH2)5[Tyr(Me)2,Ala-NH2]AVP increased renal medullary blood flow by 16 +/- 3 and 27 +/- 8%, respectively. The present experiments indicate that vasopressin V1 receptor stimulation serves to decrease renal medullary blood flow while V2 receptor stimulation appears to increase renal medullary blood flow; however, the net effect of AVP is to decrease renal medullary blood flow.

scholarly journals Autoregulation of renal medullary blood flow in rabbits

2003 ◽  
Vol 284 (1) ◽  
pp. R233-R244 ◽  
Author(s):  
Gabriela A. Eppel ◽  
Göran Bergström ◽  
Warwick P. Anderson ◽  
Roger G. Evans
Keyword(s):  
Blood Flow ◽  
Arterial Pressure ◽  
Laser Doppler Flowmetry ◽  
Systemic Arterial Pressure ◽  
Laser Doppler ◽  
Kidney Volume ◽  
Doppler Flowmetry ◽  
Medullary Blood Flow ◽  
Vasa Recta ◽  
Renal Medullary Blood Flow

We examined the extent of renal medullary blood flow (MBF) autoregulation in pentobarbital-anesthetized rabbits. Two methods for altering renal arterial pressure (RAP) were compared: the conventional method of graded suprarenal aortic occlusion and an extracorporeal circuit that allows RAP to be increased above systemic arterial pressure. Changes in MBF were estimated by laser-Doppler flowmetry, which appears to predominantly reflect erythrocyte velocity, rather than flow, in the kidney. We compared responses using a dual-fiber needle probe held in place by a micromanipulator, with responses from a single-fiber probe anchored to the renal capsule, to test whether RAP-induced changes in kidney volume confound medullary laser-Doppler flux (MLDF) measurements. MLDF responses were similar for both probe types and both methods for altering RAP. MLDF changed little as RAP was altered from 50 to ≥170 mmHg (24 ± 22% change). Within the same RAP range, RBF increased by 296 ± 48%. Urine flow and sodium excretion also increased with increasing RAP. Thus pressure diuresis/natriuresis proceeds in the absence of measurable increases in medullary erythrocyte velocity estimated by laser-Doppler flowmetry. These data do not, however, exclude the possibility that MBF is increased with increasing RAP in this model, because vasa recta recruitment may occur.

Abstract P166: The Effects of V2 Receptor Antagonist Treatment on the Renal Medullary Circulation and Urinary Sodium Excretion in Rat

Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Yusuke Ohsaki ◽  
Takefumi Mori ◽  
Kento Akao ◽  
Yoshimi Nakamichi ◽  
Chika Takahashi ◽  
...  
Keyword(s):  
Blood Flow ◽  
Urine Volume ◽  
Urinary Sodium Excretion ◽  
Urinary Sodium ◽  
Sodium Reabsorption ◽  
No Production ◽  
Doppler Flowmetry ◽  
Medullary Blood Flow ◽  
V2 Receptor ◽  
Renal Medullary Blood Flow

Objective: V2 receptor (V2R) antagonist increases aquaresis, and was reported to have renoprotective and natriuretic effect, although the mechanism is not fully clarified. Renal medullary hemodynamics contributes sodium retention and renal injury. Therefore, the present study was designed to evaluate the effect of V2R antagonist on renal medullary blood flow. Methods: Catheter was inserted in femoral artery and vein of anesthetized SD rats to monitor blood pressure (BP), heart rate (HR) and to infuse drugs, respectively. Renal medullary blood flow (MBF) and renal medullary oxygen pressure (pO2) were measured with laser-Doppler flowmetry or oxygen microelectrode, respectively. V2R antagonist, OPC-31260 (OPC, 0.25mg/kg bw/h) or furosemide (Furo, 0.5mg/kg bw/h) was intravenously administrated for 90min. Urine was collected in 30 min interval and urinary sodium (UNaV), hydrogen peroxide (UH2O2V) and [nitrate + nitrite] (UNOxV) excretion were measured. Results: OPC and Furo treatment did not change BP and HR. Urine volume was significantly increased by OPC (1.1+0.2 to 6.1+0.5 g/30 min) and Furo (1.4+0.6 to 4.7+0.3 g/30 min) treatment but was not different between groups. MBF was significantly decreased in Furo (12+4% decrease from baseline), while OPC did not changed MBF (1+3% increase from baseline). pO2 was significantly increased by both OPC and Furo treatment (20+6 and 27+10% increase from baseline, respectively). UNaV was significantly increased in OPC (0.10+0.02 to 0.44+0.05 mEq/30 min) and Furo (0.14+0.08 to 0.69+0.06 mEq/30 min) treatment, the increase of UNaV was significantly higher in Furo than OPC group. UH2O2V was significantly increased by Furo treatment (16+4 to 28+6 nmol/30 min), while did not change in OPC treatment (10+2 to 19+4 nmol/30 min). UNOx was significantly increased in OPC treatment (211+30 to 376+45 nmol/30 min), while did not change in Furo treatment (142+27 to 237+75 nmol/30 min). Conclusion: OPC treatment increased NO production. Increased NO could contribute to decrease of sodium reabsorption, result in increase of renal medullary pO2. This scheme could be one on the mechanisms of renal protective effect by V2R antagonist treatment.

Peculiarities of microcirculation in periodont tissues in children of key age groups sufficient type 1 diabetes. Part II

2019 ◽  
Vol 24 (2) ◽  
pp. 108-119 ◽  
Author(s):  
B. N. Davydov ◽  
D. A. Domenyuk ◽  
S. V. Dmitrienko
Keyword(s):  
Diabetes Mellitus ◽  
Blood Flow ◽  
Type 1 Diabetes ◽  
Type 1 Diabetes Mellitus ◽  
Laser Doppler Flowmetry ◽  
Laser Doppler ◽  
Diabetic Microangiopathy ◽  
Healthy Children ◽  
Doppler Flowmetry

Relevance. Morpho-functional changes in peripheral circulation established in type 1 diabetes mellitus correlate with changes in central hemodynamics, allowing the use of microcirculation indicators as diagnostic and prognostic criteria for assessing the degree of functional vascular disorders. Identifcation of microcirculation features of the blood by the method of laser Doppler flowmetry in children with different experience of type 1 diabetes in key age categories.Materials and methods. The study included 67 children with type 1 diabetes mellitus aged 12-15 years with an experience of the disease from six months to ten years. The comparison group consisted of 38 healthy children. The state of the microvasculature was assessed by laser Doppler flowmetry using a laser analyzer for capillary blood flow LAKK-OP.Results. In children with an experience of type 1 diabetes of less than two years, microcirculation disorders in periodontal tissues correspond to the hyperemic form, accompanied by increased perfusion, a decrease in the amplitude of low-frequency oscillations, increased heart rate, high blood flling, and blood flow bypass. For children with an endocrinopathy experience of more than three years, microcirculation disorders correspond to a stagnant form, combined with a decrease in perfusion due to stagnation of blood in the venular link, endothelial domination with suppression of neurogenic and cardiac fluctuations, low efciency and redistribution of blood flow in favor of the nutritive link.Conclusions. With the increase in experience, the degree of compensation of type 1 diabetes, the progression of diabetic microangiopathy, it is advisable to designate two stages of development of microcirculatory disorders. Early – compensatory with active adaptation, including neurogenic and endothelial regulation mechanisms. Late – decompensation with passive adaptation, supporting the effectiveness of microcirculation due to myogenic control of regulation, shunting and increasing the rate of blood outflow.

Role of renal medullary adenosine in the control of blood flow and sodium excretion

1999 ◽  
Vol 276 (3) ◽  
pp. R790-R798 ◽  
Author(s):  
Ai-Ping Zou ◽  
Kasem Nithipatikom ◽  
Pin-Lan Li ◽  
Allen W. Cowley
Keyword(s):  
Blood Flow ◽  
Sodium Excretion ◽  
Renal Medulla ◽  
Urine Flow ◽  
Doppler Flowmetry ◽  
Blood Flows ◽  
Medullary Blood Flow ◽  
Adenosine Concentration ◽  
Interstitial Infusion

This study determined the levels of adenosine in the renal medullary interstitium using microdialysis and fluorescence HPLC techniques and examined the role of endogenous adenosine in the control of medullary blood flow and sodium excretion by infusing the specific adenosine receptor antagonists or agonists into the renal medulla of anesthetized Sprague-Dawley rats. Renal cortical and medullary blood flows were measured using laser-Doppler flowmetry. Analysis of microdialyzed samples showed that the adenosine concentration in the renal medullary interstitial dialysate averaged 212 ± 5.2 nM, which was significantly higher than 55.6 ± 5.3 nM in the renal cortex ( n = 9). Renal medullary interstitial infusion of a selective A1antagonist, 8-cyclopentyl-1,3-dipropylxanthine (DPCPX; 300 pmol ⋅ kg−1 ⋅ min−1, n = 8), did not alter renal blood flows, but increased urine flow by 37% and sodium excretion by 42%. In contrast, renal medullary infusion of the selective A2 receptor blocker 3,7-dimethyl-1-propargylxanthine (DMPX; 150 pmol ⋅ kg−1 ⋅ min−1, n = 9) decreased outer medullary blood flow (OMBF) by 28%, inner medullary blood flows (IMBF) by 21%, and sodium excretion by 35%. Renal medullary interstitial infusion of adenosine produced a dose-dependent increase in OMBF, IMBF, urine flow, and sodium excretion at doses from 3 to 300 pmol ⋅ kg−1 ⋅ min−1( n = 7). These effects of adenosine were markedly attenuated by the pretreatment of DMPX, but unaltered by DPCPX. Infusion of a selective A3receptor agonist, N 6-benzyl-5′-( N-ethylcarbonxamido)adenosine (300 pmol ⋅ kg−1 ⋅ min−1, n = 6) into the renal medulla had no effect on medullary blood flows or renal function. Glomerular filtration rate and arterial pressure were not changed by medullary infusion of any drugs. Our results indicate that endogenous medullary adenosine at physiological concentrations serves to dilate medullary vessels via A2 receptors, resulting in a natriuretic response that overrides the tubular A1 receptor-mediated antinatriuretic effects.

Measurement of Colonic Blood Flow with Laser Doppler Flowmetry

1986 ◽  
Vol 21 (7) ◽  
pp. 871-880 ◽  
Author(s):  
H. Ahn ◽  
J. Lindhagen ◽  
O. Lundgren
Keyword(s):  
Blood Flow ◽  
Laser Doppler Flowmetry ◽  
Laser Doppler ◽  
Doppler Flowmetry ◽  
Colonic Blood Flow
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