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Renal oxygenation changes during water loading as evaluated by BOLD MRI: Effect of NOS inhibition
Author(s) -
Haque Muhammad,
Franklin Tammy,
Prasad Pottumarthi
Publication year - 2011
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.22509
Subject(s) - oxygenation , nitric oxide , chemistry , saline , magnetic resonance imaging , kidney , tonicity , medullary cavity , endogeny , medicine , nuclear medicine , endocrinology , anesthesia , radiology
Purpose: To demonstrate a possible role for endogenous release of nitric oxide in determining the response of water loading on intrarenal oxygenation as evaluated by blood oxygenation level‐dependent (BOLD) magnetic resonance imaging (MRI). Materials and Methods: Twelve Sprague Dawley rats (weight 344.9 ± 40.6 g) were equally divided into two groups, A and B. Water loading was implemented by continuous infusion of hypotonic saline containing glucose (0.25% NaCl, 0.5% glucose). Rats in group A were subject to water loading alone, while group B rats were dosed with N‐nitro‐L‐arginine methyl ester, (L‐NAME) (10.0 mg/kg) prior to water loading. T 2 *‐weighted images of the kidneys were obtained on a Siemens 3T Verio MRI scanner using a multiple gradient recalled echo (mGRE) sequence. Results: Consistent with previous reports, group A exhibited a significant decrease in medullary R 2 * during water loading (40.64 ± 1.10 s −1 to 34.68 ± 1.49 s −1 , P < 0.05). On the other hand, in group B there was no decrease in R 2 * during water loading (48.11 ± 2.38 s −1 to 51.06 ± 2.18 s −1 ). The increased prewater loading R 2 * is due to the pretreatment with L‐NAME (40.82 ± 3.23 s −1 to 48.11 ± 2.38 s −1 , P < 0.05). Conclusion: Our data suggest for the first time a role for endogenous nitric oxide in determining the response of renal medullary oxygenation to water loading. J. Magn. Reson. Imaging 2011;33:898–901. © 2011 Wiley‐Liss, Inc.