Autoregulation of renal medullary blood flow in rabbits

被引:30
作者
Eppel, GA
Bergström, G
Anderson, WP
Evans, RG
机构
[1] Monash Univ, Dept Physiol, Melbourne, Vic 3800, Australia
[2] Univ Gothenburg, Dept Physiol, Inst Physiol & Pharmacol, Gothenburg, Sweden
关键词
laser-Doppler flowmetry; pressure diuresis; renal blood flow; renal perfusion pressure; renal medulla;
D O I
10.1152/ajpregu.00061.2002
中图分类号
Q4 [生理学];
学科分类号
071003 ;
摘要
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 greater than or equal to170 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.
引用
收藏
页码:R233 / R244
页数:12
相关论文
共 43 条
[1]   MEASUREMENT OF HEPATIC PERFUSION IN RATS BY LASER DOPPLER FLOWMETRY [J].
ALMOND, NE ;
WHEATLEY, AM .
AMERICAN JOURNAL OF PHYSIOLOGY, 1992, 262 (02) :G203-G209
[2]  
*AM PHYS SOC, 2002, AM J PHYSIOL-REG I, V283, pR281, DOI DOI 10.1152/AJPREGU.00279.2002
[3]   AUTO-REGULATION OF RENAL BLOOD-FLOW IN SPONTANEOUSLY HYPERTENSIVE RATS [J].
ARENDSHORST, WJ .
CIRCULATION RESEARCH, 1979, 44 (03) :344-349
[4]   MECHANISMS OF DISEASE - HYPOXIA OF THE RENAL MEDULLA - ITS IMPLICATIONS FOR DISEASE [J].
BREZIS, M ;
ROSEN, S .
NEW ENGLAND JOURNAL OF MEDICINE, 1995, 332 (10) :647-655
[5]   EVIDENCE FOR A RENOMEDULLARY VASODEPRESSOR SYSTEM IN RABBITS AND DOGS [J].
CHRISTY, IJ ;
WOODS, RL ;
COURNEYA, CA ;
DENTON, KM ;
ANDERSON, WP .
HYPERTENSION, 1991, 18 (03) :325-333
[6]   AUTO-REGULATION IN VASA RECTA OF THE RAT-KIDNEY [J].
COHEN, HJ ;
MARSH, DJ ;
KAYSER, B .
AMERICAN JOURNAL OF PHYSIOLOGY, 1983, 245 (01) :F32-F40
[7]   Effects of renal medullary and intravenous norepinephrine on renal antihypertensive function [J].
Correia, AG ;
Madden, AC ;
Bergström, G ;
Evans, RG .
HYPERTENSION, 2000, 35 (04) :965-970
[9]   AUTO-REGULATION OF BLOOD-FLOW IN RENAL MEDULLA OF THE RAT - NO ROLE FOR ANGIOTENSIN-II [J].
CUPPLES, WA ;
MARSH, DJ .
CANADIAN JOURNAL OF PHYSIOLOGY AND PHARMACOLOGY, 1988, 66 (06) :833-836
[10]   Renal haemodynamic effects of endothelin-1 and the ETA/ETB antagonist TAK-044 in anaesthetized rabbits [J].
Evans, RG ;
Bergström, G ;
Cotterill, E ;
Anderson, WP .
JOURNAL OF HYPERTENSION, 1998, 16 (12) :1897-1905