期刊
AMERICAN JOURNAL OF PHYSIOLOGY-RENAL PHYSIOLOGY
卷 303, 期 3, 页码 F405-F411出版社
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/ajprenal.00329.2011
关键词
tubuloglomerular feedback adaptation; saline expansion; adenosine A(1) receptor
资金
- National Institutes of Health [R01DK-28602, R01DK-56248, R01HL-094728]
- O'Brien Kidney Center for Acute Kidney Injury [P30DK-079337]
- American Heart Association [GRNT3440038]
- Department of Veterans Affairs Research Service
- National Institute of Diabetes and Digestive and Kidney Diseases [K08-DK-084305]
- National Kidney Foundation
Blantz RC, Singh P, Deng A, Thomson SC, Vallon V. Acute saline expansion increases nephron filtration and distal flow rate but maintains tubuloglomerular feedback responsiveness: role of adenosine A(1) receptors. Am J Physiol Renal Physiol 303: F405-F411, 2012. First published May 23, 2012; doi:10.1152/ajprenal.00329.2011.-Temporal adaptation of tubuloglomerular feedback (TGF) permits readjustment of the relationship of nephron filtration rate [single nephron glomerular filtration rate (SNGFR)] and early distal tubular flow rate (V-ED) while maintaining TGF responsiveness. We used closed-loop assessment of TGF in hydropenia and after acute saline volume expansion (SE; 10% body wt over 1 h) to determine whether 1) temporal adaptation of TGF occurs, 2) adenosine A(1) receptors (A(1)R) mediate TGF responsiveness, and 3) inhibition of TGF affects SNGFR, V-ED, or urinary excretion under these conditions. SNGFR was evaluated in Fromter-Wistar rats by micropuncture in 1) early distal tubules (ambient flow at macula densa), 2) recollected from early distal tubules while 12 nl/min isotonic fluid was added to late proximal tubule (increased flow to macula densa), and 3) from proximal tubules of same nephrons (zero flow to macula densa). SE increased both ambient SNGFR and V-ED compared with hydropenia, whereas TGF responsiveness (proximal-distal difference in SNGFR, distal SNGFR response to adding fluid to proximal tubule) was maintained, demonstrating TGF adaptation. A(1)R blockade completely inhibited TGF responsiveness during SE and made V-ED more susceptible to perturbation in proximal tubular flow, but did not alter ambient SNGFR or V-ED. Greater urinary excretion of fluid and Na+ with A(1)R blockade may reflect additional effects on the distal nephron in hydropenia and SE. In conclusion, A(1)R-independent mechanisms adjust SNGFR and V-ED to higher values after SE, which facilitates fluid and Na+ excretion. Concurrently, TGF adapts and stabilizes early distal delivery at the new setpoint in an A(1)R-dependent mechanism.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据