AJP - Renal Ad Instruments
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Renal Physiol 295: F904-F911, 2008. First published July 16, 2008; doi:10.1152/ajprenal.90377.2008
0363-6127/08 $8.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
295/4/F904    most recent
90377.2008v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Botros, F. T.
Right arrow Articles by Navar, L. G.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Botros, F. T.
Right arrow Articles by Navar, L. G.

EDITORIAL FOCUS

Heme oxygenase induction attenuates afferent arteriolar autoregulatory responses

Fady T. Botros, Minolfa C. Prieto-Carrasquero, Victoria L. Martin, and L. Gabriel Navar

Department of Physiology, Hypertension and Renal Center, Tulane University Health Sciences Center, New Orleans, Louisiana

Submitted 19 June 2008 ; accepted in final form 15 July 2008

Heme oxygenases (HO-1, HO-2) catalyze conversion of heme to iron, carbon monoxide (CO), and biliverdin/bilirubin. We studied the effects of renal HO-1 induction on afferent arteriole (Aff-Art) autoregulatory responses to increases in renal perfusion pressure (RPP). Rats were treated with hemin and SnCl2 to induce HO-1, and Aff-Art autoregulatory responses were evaluated using the rat blood-perfused juxtamedullary nephron preparation. Renal HO-1 expression was significantly increased in hemin- and SnCl2-treated rats, while HO-2 was not altered. Aff-Art autoregulatory constrictor responses to increases in RPP from 100 to 150 mmHg were attenuated in hemin- and SnCl2-treated rats compared with control rats (+1.1 ± 3.3, n = 9 and +4.4 ± 5.3, n = 9 vs. –14.2 ± 1.5%, n = 10, respectively) (P < 0.05). Acute HO inhibition with chromium mesoporphyrin (CrMP; 15 µmol/l) restored Aff-Art autoregulatory responses in hemin- and SnCl2-treated rats. Superfusing Aff-Arts from control rats with 100 µmol/l biliverdin did not alter autoregulatory responses; however, superfusion with 1 mmol/l CO significantly attenuated autoregulatory responses to increases in RPP from 100 to 150 mmHg (+3.3 ± 5.4 vs. –16.6 ± 3.8%, n = 6) (P < 0.05). Acute soluble guanylate cyclase inhibition with 10 µmol/l ODQ restored Aff-Art autoregulatory responses in hemin-treated rats. Immunohistochemistry shows HO-2 to be expressed mainly in epithelial cells with weak staining in proximal tubules, interlobular arteries, and Aff-Arts. In hemin- and SnCl2-treated rats, HO-1 was induced in tubular epithelial cells but not interlobular arteries and Aff-Arts. We conclude that induction of renal HO-1 attenuates Aff-Art constrictor responses to increases in RPP via increasing CO production from tubular epithelial cells, suggesting that an augmented HO system in pathophysiological conditions modulates renal autoregulation.

hemin; carbon monoxide; biliverdin; bilirubin; autoregulation; kidney; tin chloride; soluble guanylate cyclase


Address for reprint requests and other correspondence: F. T. Botros, Dept. of Physiology, Hypertension and Renal Center, Tulane Univ. Health Sciences Center, 1430 Tulane Ave., SL39, New Orleans, LA 70112 (e-mail: fbotros{at}tulane.edu)






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online
Copyright © 2008 by the American Physiological Society.