|
|
||||||||
Division of Cardiology, Department of Internal Medicine, Virginia Commonwealth University, Richmond, Virginia 23298-0281
Chronic systemic hypoxia (SH) enhances myocardial ischemic tolerance in mammals. We studied the delayed cardioprotection caused by acute SH and associated signaling mechanism. Conscious adult male mice were exposed to one or two cycles of hypoxia (H; 10% O2) or normoxia (21% O2) for various durations (30 min, 2 h, 4 h) followed by 24 h of reoxygenation. Hearts were isolated 24 h later and subjected to ischemia-reperfusion in a Langendorff model. Infarct size was reduced in mice pretreated with one (H4h) or two cycles (H4hx2) of 4 h SH compared with normoxia mice (P < 0.05), which was abolished by an inducible nitric oxide synthase (NOS2) inhibitor (S-methylisothiourea, 3 mg/kg) given before SH or ischemia. H4hx2 also failed to reduce infarct size in NOS2 knockout mice. Cyclooxygenase-2 (COX-2) inhibitor (NS-398, 10 mg/kg) did not block the protection given either before H4hx2 or ischemia. A two- to three fold increase in myocardial NOS2 expression was observed in H4h, H2hx2, and H4hx2 (P < 0.05), whereas endothelial NOS (NOS3) or COX-2 remained unchanged. We conclude that acute SH induces delayed cardioprotection, which is triggered and mediated by NOS2, but not by NOS3 or COX-2.
ischemia; myocardial infarction; inducible nitric oxide synthase; cyclooxygenase-2; adaptive cardioprotection
This article has been cited by other articles:
![]() |
P. La Padula, J. Bustamante, A. Czerniczyniec, and L. E. Costa Time course of regression of the protection conferred by simulated high altitude to rat myocardium: correlation with mtNOS J Appl Physiol, September 1, 2008; 105(3): 951 - 957. [Abstract] [Full Text] [PDF] |
||||
![]() |
F. N. Salloum, A. Abbate, A. Das, J.-E. Houser, C. A. Mudrick, I. Z. Qureshi, N. N. Hoke, S. K. Roy, W. R. Brown, S. Prabhakar, et al. Sildenafil (Viagra) attenuates ischemic cardiomyopathy and improves left ventricular function in mice Am J Physiol Heart Circ Physiol, March 1, 2008; 294(3): H1398 - H1406. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. Belaidi, P. C. Beguin, P. Levy, C. Ribuot, and D. Godin-Ribuot Prevention of HIF-1 activation and iNOS gene targeting by low-dose cadmium results in loss of myocardial hypoxic preconditioning in the rat Am J Physiol Heart Circ Physiol, February 1, 2008; 294(2): H901 - H908. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Natarajan, F. N. Salloum, B. J. Fisher, R. C. Kukreja, and A. A. Fowler III Hypoxia Inducible Factor-1 Activation by Prolyl 4-Hydroxylase-2 Gene Silencing Attenuates Myocardial Ischemia Reperfusion Injury Circ. Res., January 6, 2006; 98(1): 133 - 140. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. C. Beguin, M. Joyeux-Faure, D. Godin-Ribuot, P. Levy, and C. Ribuot Acute intermittent hypoxia improves rat myocardium tolerance to ischemia J Appl Physiol, September 1, 2005; 99(3): 1064 - 1069. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. La Padula and L. E. Costa Effect of sustained hypobaric hypoxia during maturation and aging on rat myocardium. I. Mechanical activity J Appl Physiol, June 1, 2005; 98(6): 2363 - 2369. [Abstract] [Full Text] [PDF] |
||||
![]() |
X. Jiang, E. Shi, Y. Nakajima, S. Sato, K. Ohno, and H. Yue Cyclooxygenase-1 Mediates the Final Stage of Morphine-Induced Delayed Cardioprotection in Concert With Cyclooxygenase-2 J. Am. Coll. Cardiol., May 17, 2005; 45(10): 1707 - 1715. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. Xi, M. Taher, C. Yin, F. Salloum, and R. C. Kukreja Cobalt chloride induces delayed cardiac preconditioning in mice through selective activation of HIF-1{alpha} and AP-1 and iNOS signaling Am J Physiol Heart Circ Physiol, December 1, 2004; 287(6): H2369 - H2375. [Abstract] [Full Text] [PDF] |
||||
![]() |
Z. Xia, R. Xia, H.-T. Lan, T. Luo, Q.-Z. Tang, Z.-Y. Xia, and X.-Y. Liu Systemic ischemic preconditioning plus hemodilution enhanced early functional recovery of reperfused heart in the rabbits Interactive CardioVascular and Thoracic Surgery, September 1, 2004; 3(3): 528 - 532. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. Wang, E. Kodani, J. Wang, S. X. Zhang, H. Takano, X.-L. Tang, and R. Bolli Cardioprotection During the Final Stage of the Late Phase of Ischemic Preconditioning Is Mediated by Neuronal NO Synthase in Concert With Cyclooxygenase-2 Circ. Res., July 9, 2004; 95(1): 84 - 91. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. L. Semenza O2-regulated gene expression: transcriptional control of cardiorespiratory physiology by HIF-1 J Appl Physiol, March 1, 2004; 96(3): 1173 - 1177. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |