![]() |
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
CARDIOVASCULAR
Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan (W.-C.L., P.-J.L., W.-Y.H., C.-J.T.); and Genomics Research Center, Academia Sinica, Taipei, Taiwan (M.H.)
Carbon monoxide (CO) has been identified as an endogenous biological messenger in the brain. Heme oxygenase (HO) catalyzes the metabolism of heme to CO and biliverdin. Previously, we have shown the involvement of CO in central cardiovascular regulation, baroreflex modulation, and glutaminergic neuro-transmission in the nucleus tractus solitarii (NTS) of rats. In this study, we examined which HO isoform could be induced after hemin injection in the NTS. We also investigated their in situ distributions in the NTS after induction. Male Sprague-Dawley rats were anesthetized with urethane, and blood pressure was monitored intra-arterially. Unilateral microinjection of hemin (1 nmol), a heme molecule cleaved by HO to yield CO, produced significant decrease in blood pressure and heart rate. These cardiovascular effects of hemin were attenuated by prior administration of HO inhibitor zinc protoporphyrin IX (ZnPPIX). Microinjection of hemin into NTS resulted in significant induction of HO-1 protein expression in situ. Pretreatment of ZnPPIX significantly inhibited the HO-1 induction after hemin injection. No significant changes of HO-2 expression were found after hemin injection and ZnPPIX pretreatment. The in situ inductions of the HO-1 protein expression were further confirmed to be in glial cells and neurons after hemin injections into the NTS. These results indicated HO-1 but not HO-2 might be responsible for the generation of CO and contribute to central control of cardiovascular effects.
Address correspondence to: Dr. Ching-Jiunn Tseng, Department of Medical Education and Research, Kaohsiung Veterans General Hospital, 386 Ta-Chung 1st Road, Kaohsiung, Taiwan. E-mail: cjtseng{at}isca.vghks.gov.tw
This article has been cited by other articles:
![]() |
D. E. Stec, H. A. Drummond, and T. Vera Role of Carbon Monoxide in Blood Pressure Regulation Hypertension, March 1, 2008; 51(3): 597 - 604. [Full Text] [PDF] |
||||
![]() |
W.-Y. Ho, P.-J. Lu, M. Hsiao, H.-R. Hwang, Y.-C. Tseng, M.-H. Yen, and C.-J. Tseng Adenosine Modulates Cardiovascular Functions Through Activation of Extracellular Signal-Regulated Kinases 1 and 2 and Endothelial Nitric Oxide Synthase in the Nucleus Tractus Solitarii of Rats Circulation, February 12, 2008; 117(6): 773 - 780. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Vera, S. Kelsen, L. L. Yanes, J. F. Reckelhoff, and D. E. Stec HO-1 induction lowers blood pressure and superoxide production in the renal medulla of angiotensin II hypertensive mice Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2007; 292(4): R1472 - R1478. [Abstract] [Full Text] [PDF] |
||||