Recent studies from our laboratory have indicated that renal vascular smooth muscle cells metabolize arachidonic acid via a P4504A dependent pathway to 20-HETE, and that this system serves as a novel signal transduction pathway that plays a central role in the regulation of renal vascular tone by regulate the open state probability of Ca++-activated K+ channels. This proposal will examine the hypothesis that nitric oxide (NO) inhibits the production of 20-HETE in the kidney and that this contributes to its inhibitory effects on renal vascular tone and tubuloglomerular feedback. The influence of NO on the renal metabolism of arachidonic acid will be evaluated using renal microsomes, intact renal microvessels and tubules. Visible light spectroscopy will be utilized to study the binding of NO to recombinant P4504A isoforms expressed with a baculovirus and Sf9 insect cells. The effects of NO on K+ channel activity in renal vascular smooth muscle cells will be characterized using patch clamp techniques., and the relative contribution of 20-HETE versus cGMGP to these responses will be determined by altering intracellular levels of 20-HETE in the presence and absence of inhibitors of guanylyl cyclase and cGMP-dependent protein kinase. Parallel studies will determine the contribution of changes in the production of 20-HETE versus cGMP to the effects of NO on membrane potential and vascular tone in isolated perfused renal arterioles. The effects of P4504A inhibitors on the changes in arterial pressure and renal blood flow produced by NO donors and synthase inhibitors will be studied in rats to evaluate the significance of NO-20- HETE interactions in the regulation of renal and peripheral vascular tone in vivo, and tubular perfusion studies will be performed to determine the contribution of 20-HETE to the inhibitory effects of NO on tubuloglomerular feedback. Finally, the effects of changes in salt intake and circulating levels of AII on the distribution of P4504A mRNA, protein and enzyme activity along the nephron will be measured using competitive RT-PCR, Western blots and radio-chemical assays to determine whether changes in the expression of this system might contribute to the modulation of renal vascular tone and tubuloglomerular feedback associated with changes in salt intake.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Program Projects (P01)
Project #
5P01HL029587-18
Application #
6302163
Study Section
Project Start
2000-03-01
Project End
2001-02-28
Budget Start
1998-10-01
Budget End
1999-09-30
Support Year
18
Fiscal Year
2000
Total Cost
$250,581
Indirect Cost
Name
Medical College of Wisconsin
Department
Type
DUNS #
073134603
City
Milwaukee
State
WI
Country
United States
Zip Code
53226
Fan, Fan; Roman, Richard J (2017) Effect of Cytochrome P450 Metabolites of Arachidonic Acid in Nephrology. J Am Soc Nephrol 28:2845-2855
Fan, Fan; Pabbidi, Mallikarjuna R; Ge, Ying et al. (2017) Knockdown of Add3 impairs the myogenic response of renal afferent arterioles and middle cerebral arteries. Am J Physiol Renal Physiol 312:F971-F981
Rudemiller, Nathan P; Mattson, David L (2015) Candidate genes for hypertension: insights from the Dahl S rat. Am J Physiol Renal Physiol 309:F993-5
Cowley Jr, Allen W; Abe, Michiaki; Mori, Takefumi et al. (2015) Reactive oxygen species as important determinants of medullary flow, sodium excretion, and hypertension. Am J Physiol Renal Physiol 308:F179-97
Neuner, Sarah M; Wilmott, Lynda A; Hope, Kevin A et al. (2015) TRPC3 channels critically regulate hippocampal excitability and contextual fear memory. Behav Brain Res 281:69-77
Rudemiller, Nathan; Lund, Hayley; Jacob, Howard J et al. (2014) CD247 modulates blood pressure by altering T-lymphocyte infiltration in the kidney. Hypertension 63:559-64
He, Xiaofeng; Liu, Yong; Usa, Kristie et al. (2014) Ultrastructure of mitochondria and the endoplasmic reticulum in renal tubules of Dahl salt-sensitive rats. Am J Physiol Renal Physiol 306:F1190-7
Lakshmikanthan, Sribalaji; Zieba, Bartosz J; Ge, Zhi-Dong et al. (2014) Rap1b in smooth muscle and endothelium is required for maintenance of vascular tone and normal blood pressure. Arterioscler Thromb Vasc Biol 34:1486-94
Liu, Yong; Liu, Pengyuan; Yang, Chun et al. (2014) Base-resolution maps of 5-methylcytosine and 5-hydroxymethylcytosine in Dahl S rats: effect of salt and genomic sequence. Hypertension 63:827-38
Ge, Ying; Murphy, Sydney R; Lu, Yan et al. (2013) Endogenously produced 20-HETE modulates myogenic and TGF response in microperfused afferent arterioles. Prostaglandins Other Lipid Mediat 102-103:42-8

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