This Article Abstract Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Christodoulides, N. Articles by Schafer, A. I. Search for Related Content PubMed PubMed Citation Articles by Christodoulides, N. Articles by Schafer, A. I.

(Circulation. 1995;91:2306-2309.)
© 1995 American Heart Association, Inc.

Articles

Vascular Smooth Muscle Cell Heme Oxygenases Generate Guanylyl Cyclase–Stimulatory Carbon Monoxide

Nick Christodoulides, PhD; William Durante, PhD; Michael H. Kroll, MD; Andrew I. Schafer, MD

From the Houston (Tex) Veterans Affairs Medical Center and Baylor College of Medicine, Houston, Tex.

Correspondence to Andrew I. Schafer, MD, Chief, Medical Service (111), Houston VA Medical Center, 2002 Holcombe Blvd, Houston, TX 77030.

	Abstract

Top Abstract Introduction Methods Results Discussion References

 
Background Carbon monoxide (CO), like nitric oxide (NO), stimulates soluble guanylyl cyclase and thereby raises intracellular levels of cGMP. We examined the endogenous capacity of vascular smooth muscle cells (SMCs) to produce CO from heme through the activity of heme oxygenases.

Methods and Results Cultured SMCs from rat aorta (RASMCs) expressed immunoreactive inducible heme oxygenase-1 (HO-1) and constitutive HO-2. Treatment of RASMCs with hemin and sodium arsenite, which are inducers of HO-1, stimulated RASMC cGMP without stimulating nitrite release or inducible NO synthase expression, and the induced elevations of cGMP were not inhibited by the NO synthase inhibitor N^G-methyl-L-arginine. Induced CO from RASMCs likewise caused elevation of cGMP levels in platelets coincubated with the vascular cells. Zinc protoporphyrin IX, an inhibitor of HO, reversed the inducible increases in platelet cGMP.

Conclusions These results indicate that vascular SMCs have both constitutive and inducible HO activity, and they respond to specific stimuli to generate guanylyl cyclase–stimulatory CO in the same SMCs and in coincubated platelets.

Key Words: muscle, smooth • carbon monoxide • guanosine

	Introduction

Top Abstract Introduction Methods Results Discussion References

 
The role of nitric oxide (NO) as a physiological messenger molecule is clearly established. NO is produced from L-arginine by the action of NO synthases (NOSs). Also known as endothelium-derived relaxing factor, NO regulates blood vessel tone and blood flow by inhibiting smooth muscle contraction and platelet aggregation. Both of these NO-induced effects are mediated by the stimulation of soluble guanylyl cyclase, resulting in an increase in the intracellular levels of cGMP.¹

Carbon monoxide (CO) is a second simple diatomic gas molecule that shares some of the physicochemical properties of NO. Like NO, CO has the ability to bind to the iron atom of the heme moiety associated with soluble guanylyl cyclase, thereby activating the enzyme and increasing intracellular cGMP production. Exogenously added CO inhibits platelet aggregation and relaxes isolated blood vessel preparations by elevating intracellular levels of cGMP.²

CO is produced endogenously by various cell types as a byproduct of heme catabolism, in which heme oxygenase (HO) catalyzes the degradation of heme to biliverdin and CO. Two forms of HO have been identified. HO-1 is induced by diverse factors, including its substrate heme, as well as metal ions such as cobalt and arsenite.³ HO-2 is a constitutive enzyme that cannot be induced. Both forms of HO are inhibited by metal protoporphyrins, the most potent being zinc protoporphyrin IX (ZnPP-IX). There is great variability in the tissue distribution of the two isoforms of HO: HO-1 has high expression in the spleen and the liver, whereas the brain and testes have the highest levels of HO-2 expression.³

Verma et al⁴ recently reported the potential physiological role of endogenous CO as a neural messenger. HO-2 was localized to discrete brain neuronal populations in which NOS activity was absent and cGMP levels could be depleted by exposure to ZnPP-IX. Since cGMP controls vascular tone and platelet function, the aim of the present study was to investigate the role of endogenously produced CO as a potentially important vascular modulator of hemostasis. Results of these experiments suggest that the capacity of vascular SMCs to regulate vascular tone and platelet thrombus formation may be due, in part, to heme oxygenase–mediated CO production.

	Methods

Top Abstract Introduction Methods Results Discussion References

 
Culture of Rat Aortic SMCs
Rat aortic SMCs (RASMCs) were obtained from the laboratory of Dr Tim Scott-Burden (University of Texas, Houston). These cells were isolated from rat thoracic aorta by enzymatic digestion using standard methods and characterized morphologically and immunocytochemically as described previously.⁵ RASMCs were cultured serially in minimum essential medium (MEM) containing 10% (vol/vol) heat-inactivated FCS, glutamine (4 mmol/L), and the antibiotics penicillin (0.1 g/L) and streptomycin (0.2 g/L). RASMCs were passaged twice weekly by harvesting with trypsin-EDTA and were either plated as stocks at a 1:4 ratio in T75 culture flasks or seeded into six-well multiwell plates for incubation with the different reagents. Confluent monolayers of RASMCs were used between passages 10 and 20.

RASMC Incubations
RASMCs were incubated with or without various HO inducers in MEM containing 5% FCS for 24 hours. The inducers used in this study were (in µmol/L): hemin 20, cobalt chloride 100, iodoacetamide 10, and sodium arsenite 10. In indicated experiments, the inhibitor of NO synthase N^G-methyl-L-arginine (L-NMA; 0.1 mmol/L) or the inhibitor of HO ZnPP-IX (10 µmol/L) was added at the beginning of the 24-hour incubation period.

Nitrite Assay
NO in the supernatants of the RASMC monolayers was determined by measuring the levels of nitrite (the predominant oxidation product of NO) by diazotization and absorbance reading at 540 nm, as previously described.⁶ Nitrite concentrations were determined by comparison with a standard curve using sodium nitrite as a standard and water as a blank. The detection limit of this assay has been reported at 200 pmol/L.⁷

cGMP Measurements
After the 24-hour treatment period, the culture media were removed and the monolayers of cells rinsed with PBS. The RASMCs were treated with the phosphodiesterase inhibitor isobutyl methylxanthine (IBMX; 0.5 mmol/L) for 45 minutes, and then 1 mL of trichloroacetic acid (TCA; 6% wt/vol) was added. The cells were scraped off the plate, collected into Eppendorf tubes, sonicated for 20 seconds, and assayed for cGMP with a commercially available radioimmunoassay kit (NEN-DuPont).

Platelet Detector System
Platelets were isolated from blood obtained from healthy volunteers, and washed platelet suspensions in Ca²⁺-free Tyrode's buffer supplemented with HEPES (2 mmol/L) were prepared as previously described.⁸ The washed platelet suspensions were then treated with IBMX (0.1 mmol/L) and added onto monolayers of RASMCs. Before the addition of the platelet suspensions to the individual wells, the media containing the various treatments were aspirated, and the RASMC monolayers were rinsed with PBS. This ensured that platelets were not exposed to the inducers and inhibitors used in the pretreatments of the RASMCs. After 45 minutes of coincubation with RASMCs, the platelet suspensions were aspirated from the wells and placed in TCA (6% wt/vol). The samples were then processed for cGMP radioimmunoassay as described above.

Western Blot Analysis
RASMCs were exposed to HO inducers for 24 hours. The cells were then lysed in gel electrophoresis sample buffer (12 mmol/L Tris-HCl, pH 6.8, 5% glycerol, 0.4% SDS), boiled for 5 minutes, sonicated for 10 seconds, and microcentrifuged at 10 000g for 10 minutes. The resulting supernatants were collected and subsequently quantified for protein. Cell extracts (50 µg) were then subjected to SDS-PAGE on a 17.5% gel. The separated proteins were transferred to a nitrocellulose membrane, and the blot was then blocked with a 5% solution of Carnation dried milk and 3% BSA in PBS for 1 hour. The blot was washed with PBS and incubated for 1 hour at 24°C with an HO-1–specific antibody (OSA-100) diluted 400-fold. The blot was washed again with PBS and incubated for an additional 1 hour with goat alkaline phosphatase–conjugated F(ab')₂ fragment against rabbit IgG, diluted 2000-fold. After the final washes, the immune-complexed bands were visualized with nitro blue tetrazolium and BCIP. This procedure allowed visual comparison of the relative staining intensities of individual bands as an indication of induction of HO-1. Alternatively, an HO-2–specific antibody (OSA-200) was used as the primary antibody to detect the presence of the constitutive HO-2 protein in these cells. In a parallel experiment, samples from control and hemin-treated (20.0 µmol/L), sodium arsenite–treated (10.0 µmol/L), or interleukin 1ß–treated (IL-1ß, 3.0 ng/mL) RASMCs were exposed to Western blot analysis using a mouse monoclonal antibody specific for inducible NOS (iNOS).

Materials
Hemin, sodium m-arsenite, cobalt chloride, iodoacetamide, IBMX, creatine phosphate, creatine phosphokinase, fatty acid–free BSA, sodium nitrite, N-(1-naphthyl) ethylenediamine dihydrochloride, sulfanilamide, DMSO, L-NMA, TCA, and alkaline phosphatase–conjugated F(ab')₂ goat fragment against rabbit IgG were purchased from Sigma Chemical Co; 3-morpholinosydnonimine hydrochloride (SIN-1) was from Biomolecular Research Laboratories; antibiotics, MEM, FCS, L-glutamine, and trypsin-EDTA were from Gibco BRL, Life Technologies; antibodies against HO-1 (OSA-100) and HO-2 (OSA-200) were purchased from StressGen; ZnPP-IX was from Porphyrin Products; nitro blue tetrazolium, BCIP, and goat anti-mouse alkaline phosphatase–conjugated IgG (H+L) were from Upstate Biotechnology, Inc; and mouse anti-iNOS antibody was from Transduction Laboratories.

Statistical Analysis
Results are expressed as mean±SEM. Statistical analyses were performed with Student's two-tailed paired t test and ANOVA when more than two treatments were compared. Values of P<.05 were considered to be statistically significant.

	Results

Top Abstract Introduction Methods Results Discussion References

 
The two HO-specific antibodies used in the Western blot analysis, OSA-100 and OSA-200, produced bands demonstrating that RASMCs constitutively express HO-1 and HO-2, respectively (Fig 1). Western blotting of untreated RASMCs with antibody OSA-100 produced an immunoreactive band at approximately 30 kD (Fig 1A, lane 2). OSA-100 exhibited specificity for HO-1 in that it did not recognize noninducible HO-2; HO-2 was identified specifically by OSA-200 at approximately 36 kD (Fig 1B, lane 2). Treatment of RASMCs with inducers of HO-1 resulted in a significant increase in the amount of HO-1 protein (30 kD) expressed in these cells. Fig 1A (lanes 3 through 6) shows that hemin (20 µmol/L), iodoacetamide (10 µmol/L), sodium arsenite (10 µmol/L), and cobalt chloride (100 µmol/L) induced a significant increase in HO-1 expression compared with the untreated cells (lane 2). A comparison of the relative intensities of these bands revealed that sodium arsenite was the most potent of these inducers of HO-1. Using Western blot analysis with an anti-iNOS monoclonal antibody, we ruled out induction of iNOS by the heme oxygenase inducers. Samples from IL-1ß–treated RASMCs produced the iNOS band at 130 kD (Fig 1C, lane 1). The same antibody did not react with samples from control, sodium arsenite–treated, or hemin-treated RASMCs (lanes 2 through 4).

View larger version (68K): [in this window] [in a new window]   Figure 1. Western blot analysis demonstrating the presence of both the constitutive and the inducible isoforms of heme oxygenase in rat aortic smooth muscle cells (analysis of cell extracts was performed as described in "Methods"). A, Lane 1, molecular weight standards; lanes 2 through 6, samples from cells exposed to the following agents: 2, control; 3, hemin (20 µmol/L); 4, iodoacetamide (10 µmol/L); 5, sodium arsenite (10 µmol/L); and 6, cobalt chloride (100 µmol/L). The blot was exposed to OSA-100, an HO-1–specific antibody. B, Lane 1, molecular weight standards; lane 2, cell extract exposed to OSA-200, an antibody directed against HO-2. C, Lanes 1 through 4, samples from rat aortic smooth muscle cells exposed to the following agents for 24 hours: 1, interleukin-1ß (3 ng/mL); 2, sodium arsenite (10 µmol/L); 3, hemin (20 µmol/L); 4, control; 5, a sample from lipopolysaccharide-induced mouse macrophages; and 6, molecular weight standards. The blot was exposed to anti–inducible nitric oxide synthase mouse monoclonal antibody.

Since exogenous CO is known to increase intracellular cGMP concentrations, we measured RASMC cGMP to monitor the induction of HO activity. As shown in Fig 2A, 24-hour treatment of RASMCs with either 20 µmol/L hemin or 10 µmol/L sodium arsenite resulted in 36% and 290% increases of intracellular cGMP levels, respectively. Direct activation of guanylyl cyclase by the heme oxygenase inducers was ruled out, since treatment of RASMCs with hemin or sodium arsenite for 15 minutes (an incubation time too brief for HO-1 induction) did not result in cGMP elevations (data not shown). In a number of tissues, including vascular SMCs, NO generated by NOSs likewise regulates intracellular cGMP concentrations.¹ To exclude the possibility that the cGMP increases seen in Fig 2A were due to the induction of inducible NOSs, two approaches were taken. First, as shown in Fig 2B, the NOS inhibitor L-NMA (0.1 mmol/L) failed to alter the cGMP elevations induced by hemin and sodium arsenite. Second, levels of NO in the media, as determined by nitrite measurements, were not significantly affected by the above treatments (Fig 2C and 2D).

View larger version (23K): [in this window] [in a new window]   Figure 2. Bar graphs showing effect of heme oxygenase inducers on cGMP content and nitric oxide production in rat aortic smooth muscle cells. Intracellular cGMP (A and B) and extracellular nitrite levels (C and D) in the presence (B and D) or absence (A and C) of the nitric oxide synthase inhibitor NG-methyl-L-arginine (L-NMA) (0.1 mmol/L) were measured from untreated, hemin-treated (20 µmol/L), or sodium arsenite–treated (10 µmol/L) cultured cells. Results are mean±SEM of at least five separate experiments, each performed in duplicate. *Statistically significant increase in intracellular cGMP levels compared with untreated control cells. Rat aortic smooth muscle cells (RASMCs) were treated either with vehicle, with hemin (20 µmol/L), or with sodium arsenite (10 µmol/L) in the presence or absence of ZnPP-IX (10 µmol/L) for 24 hours. The treatment media were then removed, and the cell monolayers were washed with PBS. Platelets (5x108) were then coincubated with the RASMCs in the presence of isobutyl methylxanthine (0.1 mmol/L) for 45 minutes. The platelet intracellular cGMP content was then measured as described in "Methods." Results are mean±SEM of three separate experiments, each performed in duplicate.

To confirm that the hemin- and sodium arsenite–induced cGMP increases were due to HO-mediated CO production, the potent HO inhibitor ZnPP-IX was used. ZnPP-IX lowered cGMP concentrations of the RASMCs to levels 31.1% lower than those of basal controls (data not shown). This effect was not due to ZnPP-IX activation of RASMC phosphodiesterase, since all experiments were performed in the presence of IBMX, a phosphodiesterase inhibitor. We considered these results to be due to either ZnPP-IX–mediated trapping of basal NO or to ZnPP-IX–mediated inhibition of heme oxygenase and/or guanylyl cyclase.

We tested the ability of ZnPP-IX (10.0 µmol/L) to trap NO in a cell-free system using SIN-1, an NO-generating agent. The nitrite levels of SIN-1 solutions exposed to ZnPP-IX for 24 hours were not significantly different from those of untreated controls (data not shown). Therefore, the reductions of cGMP in RASMCs in the presence of ZnPP-IX are not due to trapping of basal NO by ZnPP-IX. To examine whether ZnPP-IX inhibits guanylyl cyclase itself, SMCs were exposed to sodium nitroprusside (SNP, 0.1 mmol/L), a guanylyl cyclase stimulator, in the presence or absence of ZnPP-IX. The SNP-induced increases in RASMC cGMP were reduced significantly, by 63%, in the presence of ZnPP-IX, indicating that this protoporphyrin inhibits guanylyl cyclase as well as HO.

Treatment of RASMCs with hemin or sodium arsenite also resulted in an increase of intracellular cGMP levels of coincubated platelets (Table). The increases paralleled those observed in RASMCs under the same conditions. Platelets exposed to the hemin-treated SMCs, but not to hemin itself, demonstrated a 23.6% increase in their intracellular cGMP levels. Similarly, platelets coincubated with RASMCs exposed to the more potent HO inducer sodium arsenite demonstrated a 111% increase in their intracellular cGMP levels. The addition of ZnPP-IX reversed the hemin- or sodium arsenite–induced rise in platelet cGMP concentrations, even though the platelets were not themselves exposed to the above treatments. When RASMCs were treated with ZnPP-IX alone, the basal cGMP content of the coincubated platelets was reduced by approximately 25%. To confirm that this observed decrease was not due to trapping of basal NO by ZnPP-IX, we repeated the experiment in the presence of L-NMA. L-NMA failed to reverse the ZnPP-IX–mediated reduction of basal platelet cGMP (data not shown).

View this table: [in this window] [in a new window]   Table 1. Regulation of Platelet cGMP Content by Rat Aortic Smooth Muscle Cells

	Discussion

Top Abstract Introduction Methods Results Discussion References

 
We demonstrate the expression of both the constitutive and inducible isoforms of HO in RASMCs. Treatment of RASMCs with hemin or sodium arsenite resulted in the induction of HO-1 and in a significant increase in the cGMP content of the cultured SMCs. These heme oxygenase inducers had no effect on NO production or iNOS expression by RASMCs; furthermore, the NOS inhibitor L-NMA did not alter the hemin- and sodium arsenite–induced cGMP elevations in the SMCs. Therefore, NO was excluded as the guanylyl cyclase activator in this system. Coincubation of platelets with hemin- or sodium arsenite–treated RASMCs also increased the intracellular cGMP content of the platelets. These cGMP increases were blocked by ZnPP-IX, an HO inhibitor. Furthermore, ZnPP-IX treatment of the SMCs also reduced the basal platelet cGMP levels, indicating constitutive activity of SMC HO-2 under basal conditions. Vascular SMCs thus have the capacity to generate endogenous carbon monoxide (CO).

CO shares some of the chemical and biological properties of NO.² Exogenously added CO, like NO, stimulates SMC guanylyl cyclase and causes vasorelaxation^{9 10 11 12} ; it also stimulates platelet guanylyl cyclase and inhibits platelet activation.^{13 14} CO has recently been identified as an endogenous biological messenger in the brain.⁴ An NO-independent pathway of guanylyl cyclase activation has recently been proposed in cytokine-stimulated vascular smooth muscle.¹⁵ Our results suggest that CO is the diffusible endogenous messenger molecule that stimulates the cGMP elevations produced by the hemin- and arsenite-treated RASMCs. To demonstrate that these effects were due to HO-derived CO, we used ZnPP-IX, an inhibitor of HO. However, control experiments revealed that ZnPP-IX also inhibited cGMP accumulation in SMCs in response to the guanylyl cyclase inducer SNP, indicating that ZnPP-IX inhibits guanylyl cyclase as well as HO. To circumvent the effects of ZnPP-IX on guanylyl cyclase, we developed a platelet detector system. Under these conditions, platelets coincubated with the SMCs were not directly exposed to the various inducers and/or inhibitors of SMC HO; therefore, any effects observed on the platelet cGMP content were due solely to guanylyl cyclase regulation by a diffusible SMC-derived messenger molecule. The results of these experiments demonstrated that RASMCs release CO by both constitutive and inducible heme oxygenase mechanisms to regulate platelet cGMP levels.

Our studies suggest that CO is not simply an irrelevant byproduct of heme catabolism but rather may assume physiologically important regulatory functions in the vasculature. We propose that CO is a SMC-derived messenger molecule with autocrine and paracrine actions. Thus, vessel wall–derived CO potentially serves as an endogenous regulator of vascular tone and platelet reactivity. The heme–heme oxygenase–CO and the L-arginine–NO synthase–NO systems have certain parallels. Both gas products cause vasorelaxation and platelet inhibition by elevating the cGMP content of vascular SMCs and platelets, respectively. Furthermore, both constitutive and inducible forms of heme oxygenase and NO synthase are active in the vessel wall. However, there are also some important differences between the properties of CO and NO.² It is unlikely that CO and NO represent redundant messenger molecules. Further studies will be required to elucidate the specific inducers and regulators of the enzymes that lead to the production of these biologically active simple gases.

Note added in proof. Since submission of this article, Morita et al have reported that hypoxia induces vascular SMC CO production.¹⁶

	Acknowledgments

 
This study was supported by VA Merit Review grants (Dr Schafer and Dr Kroll), National Institutes of Health grants HL-36045 (Dr Schafer) and HL-02311 (Dr Kroll); and grants from the American Heart Association, Texas Affiliate (Dr Durante), and an Established Investigator award (Dr Kroll).

Received February 14, 1995; accepted March 5, 1995.

	References

Top Abstract Introduction Methods Results Discussion References

 
1. Stamler JS, Singel DJ, Loscalzo J. Biochemistry of nitric oxide and its redox-activated forms. Science. 1992;258:1898-1902. [Abstract/Free Full Text]

2. Marks GS, Brien JF, Nakatsu K, McLauglin BE. Does carbon monoxide have a physiological function? Trends Pharmacol Sci. 1991;121:185-188.

3. Maines MD. Heme oxygenase: function, multiplicity, regulatory mechanisms, and clinical applications. FASEB J. 1988;2:2557-2568. [Abstract]

4. Verma A, Hirsch DJ, Glatt CE, Ronnett GV, Snyder SH. Carbon monoxide: a putative neural messenger. Science. 1993;259:381-384. [Abstract/Free Full Text]

5. Scott-Burden T, Resink TJ, Baur U, Burgin M, Buhler FR. Epidermal growth factor responsiveness in smooth muscle cells from hypertensive and normotensive rats. Hypertension. 1989;13:295-304. [Abstract/Free Full Text]

6. Durante W, Schini VB, Catovsky S, Kroll MH, Vanhoutte PM, Schafer AI. Plasmin potentiates the induction of nitric oxide synthesis by interleukin-1ß in vascular smooth cells. Am J Physiol. 1993;264:H617-H624. [Abstract/Free Full Text]

7. Schmidt HHH, Warner TD, Nakane M, Forstermann U, Murad F. Regulation and subcellular location of nitrogen oxide synthases in RAW264.7 macrophages. Mol Pharmacol. 1992;41:615-624. [Abstract]

8. Kroll MH, Zavoico GB, Schafer AI. Control of platelet protein kinase C activation by cyclic AMP. Biochim Biophys Acta. 1988;970:61-67. [Medline] [Order article via Infotrieve]

9. Vedernikov YP, Graser T, Vanin AF. Similar endothelium-independent arterial relaxation by carbon monoxide and nitric oxide. Biomed Biochim Acta. 1989;48:601-603. [Medline] [Order article via Infotrieve]

10. Graser T, Vedernikov YP, Li DS. Study on the mechanism of carbon monoxide induced endothelium-independent relaxation in porcine coronary artery and vein. Biomed Biochim Acta. 1990;49:293-296. [Medline] [Order article via Infotrieve]

11. Ramos KS, Lin H, McGrath JJ. Modulation of cyclic guanosine monophosphate levels in cultured smooth muscle cells by carbon monoxide. Biochem Pharmacol. 1989;38:1368-1370. [Medline] [Order article via Infotrieve]

12. Lin H, McGrath JJ. Carbon monoxide effects on calcium levels in vascular smooth muscle. Life Sci. 1988;43:1813-1816. [Medline] [Order article via Infotrieve]

13. Mansouri A, Perry CA. Inhibition of platelet ADP and serotonin release by carbon monoxide and in cigarette smokers. Experientia. 1984;40:515-517. [Medline] [Order article via Infotrieve]

14. Brune B, Ullrich V. Inhibition of platelet aggregation by carbon monoxide is mediated by activation of guanylyl cyclase. Mol Pharmacol. 1987;32:497-504. [Abstract]

15. Beasley D, McGuiggin M. Interleukin 1 activates soluble guanylyl cyclase in human vascular smooth muscle cells through a novel nitric oxide-independent pathway. J Exp Med. 1994;179:71-80.[Abstract/Free Full Text]

16. Morita T, Perrella MA, Lee ME, Kourembanas S. Smooth muscle cell-derived carbon monoxide is a regulator of vascular cGMP. Proc Natl Acad Sci U S A. 1995;92:1475-1479.[Abstract/Free Full Text]

This article has been cited by other articles:

				B. D. Lamon, F. F. Zhang, N. Puri, S. V. Brodsky, M. S. Goligorsky, and A. Nasjletti Dual Pathways of Carbon Monoxide-Mediated Vasoregulation: Modulation by Redox Mechanisms Circ. Res., October 9, 2009; 105(8): 775 - 783. [Abstract] [Full Text] [PDF]

				A. Kanu and C. W. Leffler Roles of Glia Limitans Astrocytes and Carbon Monoxide in Adenosine Diphosphate-Induced Pial Arteriolar Dilation in Newborn Pigs Stroke, March 1, 2009; 40(3): 930 - 935. [Abstract] [Full Text] [PDF]

				R. A. Dombkowski, N. L. Whitfield, R. Motterlini, Y. Gao, and K. R. Olson Effects of carbon monoxide on trout and lamprey vessels Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2009; 296(1): R141 - R149. [Abstract] [Full Text] [PDF]

				X. Qin, H. Kwansa, E. Bucci, S. Dore, D. Boehning, D. Shugar, and R. C. Koehler Role of heme oxygenase-2 in pial arteriolar response to acetylcholine in mice with and without transfusion of cell-free hemoglobin polymers Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2008; 295(2): R498 - R504. [Abstract] [Full Text] [PDF]

				H. Zhao, R. J. Wong, T. C. Doyle, N. Nayak, H. J. Vreman, C. H. Contag, and D. K. Stevenson Regulation of Maternal and Fetal Hemodynamics by Heme Oxygenase in Mice Biol Reprod, April 1, 2008; 78(4): 744 - 751. [Abstract] [Full Text] [PDF]

				C. J. Mingone, M. Ahmad, S. A. Gupte, J. L. Chow, and M. S. Wolin Heme oxygenase-1 induction depletes heme and attenuates pulmonary artery relaxation and guanylate cyclase activation by nitric oxide Am J Physiol Heart Circ Physiol, March 1, 2008; 294(3): H1244 - H1250. [Abstract] [Full Text] [PDF]

				A. Kanu and C. W. Leffler Carbon monoxide and Ca2+-activated K+ channels in cerebral arteriolar responses to glutamate and hypoxia in newborn pigs Am J Physiol Heart Circ Physiol, November 1, 2007; 293(5): H3193 - H3200. [Abstract] [Full Text] [PDF]

				A. Kanu, J. Whitfield, and C. W. Leffler Carbon monoxide contributes to hypotension-induced cerebrovascular vasodilation in piglets Am J Physiol Heart Circ Physiol, November 1, 2006; 291(5): H2409 - H2414. [Abstract] [Full Text] [PDF]

				S. Chlopicki, R. Olszanecki, E. Marcinkiewicz, M. Lomnicka, and R. Motterlini Carbon monoxide released by CORM-3 inhibits human platelets by a mechanism independent of soluble guanylate cyclase Cardiovasc Res, July 15, 2006; 71(2): 393 - 401. [Abstract] [Full Text] [PDF]

				S. W. Ryter, J. Alam, and A. M. K. Choi Heme Oxygenase-1/Carbon Monoxide: From Basic Science to Therapeutic Applications Physiol Rev, April 1, 2006; 86(2): 583 - 650. [Abstract] [Full Text] [PDF]

				F. K. Johnson, R. A. Johnson, W. Durante, K. E. Jackson, B. K. Stevenson, and K. J. Peyton Metabolic syndrome increases endogenous carbon monoxide production to promote hypertension and endothelial dysfunction in obese Zucker rats Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2006; 290(3): R601 - R608. [Abstract] [Full Text] [PDF]

				P. Achouh, S. Simonet, C. Badier-Commander, C. Chardigny, C. Vayssettes-Courchay, R. Zegdi, Z. Khabbaz, J.-N. Fabiani, and T. J. Verbeuren The induction of heme oxygenase 1 decreases contractility in human internal thoracic artery and radial artery grafts J. Thorac. Cardiovasc. Surg., December 1, 2005; 130(6): 1573 - 1580. [Abstract] [Full Text] [PDF]

				L. Wu and R. Wang Carbon Monoxide: Endogenous Production, Physiological Functions, and Pharmacological Applications Pharmacol. Rev., December 1, 2005; 57(4): 585 - 630. [Abstract] [Full Text] [PDF]

				H. Resch, C. Zawinka, G. Weigert, L. Schmetterer, and G. Garhofer Inhaled Carbon Monoxide Increases Retinal and Choroidal Blood Flow in Healthy Humans Invest. Ophthalmol. Vis. Sci., November 1, 2005; 46(11): 4275 - 4280. [Abstract] [Full Text] [PDF]

				F. J. Teran, R. A. Johnson, B. K. Stevenson, K. J. Peyton, K. E. Jackson, S. D. Appleton, W. Durante, and F. K. Johnson Heme oxygenase-derived carbon monoxide promotes arteriolar endothelial dysfunction and contributes to salt-induced hypertension in Dahl salt-sensitive rats Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2005; 288(3): R615 - R622. [Abstract] [Full Text] [PDF]

				E. Barkoudah, J. H. Jaggar, and C. W. Leffler The permissive role of endothelial NO in CO-induced cerebrovascular dilation Am J Physiol Heart Circ Physiol, October 1, 2004; 287(4): H1459 - H1465. [Abstract] [Full Text] [PDF]

				F. K. Johnson, W. Durante, K. J. Peyton, and R. A. Johnson Heme oxygenase-mediated endothelial dysfunction in DOCA-salt, but not in spontaneously hypertensive, rat arterioles Am J Physiol Heart Circ Physiol, May 1, 2004; 286(5): H1681 - H1687. [Abstract] [Full Text] [PDF]

				D. Sacerdoti, N. G. Abraham, A. O. Oyekan, L. Yang, A. Gatta, and J. C. McGiff Role of the Heme Oxygenases in Abnormalities of the Mesenteric Circulation in Cirrhotic Rats J. Pharmacol. Exp. Ther., February 1, 2004; 308(2): 636 - 643. [Abstract] [Full Text] [PDF]

				Q. Xi, D. Tcheranova, H. Parfenova, B. Horowitz, C. W. Leffler, and J. H. Jaggar Carbon monoxide activates KCa channels in newborn arteriole smooth muscle cells by increasing apparent Ca2+ sensitivity of {alpha}-subunits Am J Physiol Heart Circ Physiol, February 1, 2004; 286(2): H610 - H618. [Abstract] [Full Text] [PDF]

				P. Koneru and C. W. Leffler Role of cGMP in carbon monoxide-induced cerebral vasodilation in piglets Am J Physiol Heart Circ Physiol, January 1, 2004; 286(1): H304 - H309. [Abstract] [Full Text] [PDF]

				G. Farrugia, S. Lei, X. Lin, S. M. Miller, K. A. Nath, C. D. Ferris, M. Levitt, and J. H. Szurszewski A major role for carbon monoxide as an endogenous hyperpolarizing factor in the gastrointestinal tract PNAS, July 8, 2003; 100(14): 8567 - 8570. [Abstract] [Full Text] [PDF]

				C. W. Leffler, L. Balabanova, A. L. Fedinec, C. M. Waters, and H. Parfenova Mechanism of glutamate stimulation of CO production in cerebral microvessels Am J Physiol Heart Circ Physiol, June 5, 2003; 285(1): H74 - H80. [Abstract] [Full Text] [PDF]

				J. S. Naik and B. R. Walker Heme oxygenase-mediated vasodilation involves vascular smooth muscle cell hyperpolarization Am J Physiol Heart Circ Physiol, June 5, 2003; 285(1): H220 - H228. [Abstract] [Full Text] [PDF]

				C. W. Leffler, L. Balabanova, C. D. Sullivan, X. Wang, A. L. Fedinec, and H. Parfenova Regulation of CO production in cerebral microvessels of newborn pigs Am J Physiol Heart Circ Physiol, June 5, 2003; 285(1): H292 - H297. [Abstract] [Full Text] [PDF]

				J. F. Ndisang, L. Wu, W. Zhao, and R. Wang Induction of heme oxygenase-1 and stimulation of cGMP production by hemin in aortic tissues from hypertensive rats Blood, May 15, 2003; 101(10): 3893 - 3900. [Abstract] [Full Text] [PDF]

				Y.-H. Chen, S.-F. Yet, and M. A. Perrella Role of Heme Oxygenase-1 in the Regulation of Blood Pressure and Cardiac Function Experimental Biology and Medicine, May 1, 2003; 228(5): 447 - 453. [Abstract] [Full Text] [PDF]

				A. I. Goodman, S. Quan, L. Yang, A. Synghal, and N. G. Abraham Functional Expression of Human Heme Oxygenase-1 Gene in Renal Structure of Spontaneously Hypertensive Rats Experimental Biology and Medicine, May 1, 2003; 228(5): 454 - 458. [Abstract] [Full Text] [PDF]

				X.-M. Liu, G. B. Chapman, K. J. Peyton, A. I. Schafer, and W. Durante Antiapoptotic Action of Carbon Monoxide on Cultured Vascular Smooth Muscle Cells Experimental Biology and Medicine, May 1, 2003; 228(5): 572 - 575. [Abstract] [Full Text] [PDF]

				E. Fiumana, H. Parfenova, J. H. Jaggar, and C. W. Leffler Carbon monoxide mediates vasodilator effects of glutamate in isolated pressurized cerebral arterioles of newborn pigs Am J Physiol Heart Circ Physiol, April 1, 2003; 284 (4): H1073 - H1079. [Abstract] [Full Text] [PDF]

				J. S. Naik, T. L. O'Donaughy, and B. R. Walker Endogenous carbon monoxide is an endothelial-derived vasodilator factor in the mesenteric circulation Am J Physiol Heart Circ Physiol, March 1, 2003; 284(3): H838 - H845. [Abstract] [Full Text] [PDF]

				J. S. Winestone, C. Bonner, and C. W. Leffler Carbon Monoxide as an Attenuator of Vasoconstriction in Piglet Cerebral Arterioles Experimental Biology and Medicine, January 1, 2003; 228(1): 46 - 50. [Abstract] [Full Text] [PDF]

				F. K. Johnson, W. Durante, K. J. Peyton, and R. A. Johnson Heme Oxygenase Inhibitor Restores Arteriolar Nitric Oxide Function in Dahl Rats Hypertension, January 1, 2003; 41(1): 149 - 155. [Abstract] [Full Text] [PDF]

				N. G. Abraham, S. Quan, P. A. Mieyal, L. Yang, T. Burke-Wolin, C. J. Mingone, A. I. Goodman, A. Nasjletti, and M. S. Wolin Modulation of cGMP by human HO-1 retrovirus gene transfer in pulmonary microvessel endothelial cells Am J Physiol Lung Cell Mol Physiol, November 1, 2002; 283(5): L1117 - L1124. [Abstract] [Full Text] [PDF]

				J. H. Jaggar, C. W. Leffler, S. Y. Cheranov, D. Tcheranova, S. E, and X. Cheng Carbon Monoxide Dilates Cerebral Arterioles by Enhancing the Coupling of Ca2+ Sparks to Ca2+-Activated K+ Channels Circ. Res., October 4, 2002; 91(7): 610 - 617. [Abstract] [Full Text] [PDF]

				H. Kaneda, M. Ohno, J. Taguchi, M. Togo, H. Hashimoto, K. Ogasawara, T. Aizawa, N. Ishizaka, and R. Nagai Heme Oxygenase-1 Gene Promoter Polymorphism Is Associated With Coronary Artery Disease in Japanese Patients With Coronary Risk Factors Arterioscler Thromb Vasc Biol, October 1, 2002; 22(10): 1680 - 1685. [Abstract] [Full Text] [PDF]

				E. P. Carter, C. L. Hartsfield, M. Miyazono, M. Jakkula, K. G. Morris Jr., and I. F. McMurtry Regulation of heme oxygenase-1 by nitric oxide during hepatopulmonary syndrome Am J Physiol Lung Cell Mol Physiol, August 1, 2002; 283(2): L346 - L353. [Abstract] [Full Text] [PDF]

				H. Parfenova, R. A. Neff III, J. S. Alonso, B. V. Shlopov, C. N. Jamal, S. A. Sarkisova, and C. W. Leffler Cerebral vascular endothelial heme oxygenase: expression, localization, and activation by glutamate Am J Physiol Cell Physiol, December 1, 2001; 281(6): C1954 - C1963. [Abstract] [Full Text] [PDF]

				J. S. Naik and B. R. Walker Homogeneous segmental profile of carbon monoxide-mediated pulmonary vasodilation in rats Am J Physiol Lung Cell Mol Physiol, December 1, 2001; 281(6): L1436 - L1443. [Abstract] [Full Text] [PDF]

				T. Komuro, M. K. Borsody, S. Ono, L. S. Marton, B. K. Weir, Z.-D. Zhang, E. Paik, and R. L. Macdonald The Vasorelaxation of Cerebral Arteries by Carbon Monoxide Experimental Biology and Medicine, October 1, 2001; 226(9): 860 - 865. [Abstract] [Full Text] [PDF]

				W. Tschugguel, F. Stonek, Z. Zhegu, W. Dietrich, C. Schneeberger, T. Stimpfl, T. Waldhoer, W. Vycudilik, and J. C. Huber Estrogen Increases Endothelial Carbon Monoxide, Heme Oxygenase 2, and Carbon Monoxide-Derived cGMP by a Receptor-Mediated System J. Clin. Endocrinol. Metab., August 1, 2001; 86(8): 3833 - 3839. [Abstract] [Full Text] [PDF]

				N. L. Jernigan, T. L. O'Donaughy, and B. R. Walker Correlation of HO-1 expression with onset and reversal of hypoxia-induced vasoconstrictor hyporeactivity Am J Physiol Heart Circ Physiol, July 1, 2001; 281(1): H298 - H307. [Abstract] [Full Text] [PDF]

				F. Zhang, J.-I. Kaide, Y. Wei, H. Jiang, C. Yu, M. Balazy, N. G. Abraham, W. Wang, and A. Nasjletti Carbon monoxide produced by isolated arterioles attenuates pressure-induced vasoconstriction Am J Physiol Heart Circ Physiol, July 1, 2001; 281(1): H350 - H358. [Abstract] [Full Text] [PDF]

				D.T. Bau, J.R. Gurr, and K.Y. Jan Nitric oxide is involved in arsenite inhibition of pyrimidine dimer excision Carcinogenesis, May 1, 2001; 22(5): 709 - 716. [Abstract] [Full Text] [PDF]

				C. W. Leffler, A. Nasjletti, R. A. Johnson, and A. L. Fedinec Contributions of prostacyclin and nitric oxide to carbon monoxide-induced cerebrovascular dilation in piglets Am J Physiol Heart Circ Physiol, April 1, 2001; 280(4): H1490 - H1495. [Abstract] [Full Text] [PDF]

				R. Wang, Z. Wang, L. Wu, S. T. Hanna, and R. Peterson-Wakeman Reduced Vasorelaxant Effect of Carbon Monoxide in Diabetes and the Underlying Mechanisms Diabetes, January 1, 2001; 50(1): 166 - 174. [Abstract] [Full Text]

				Y. Morimoto, W. Durante, D. G. Lancaster, J. Klattenhoff, and F. K. Tittel Real-time measurements of endogenous CO production from vascular cells using an ultrasensitive laser sensor Am J Physiol Heart Circ Physiol, January 1, 2001; 280(1): H483 - H488. [Abstract] [Full Text] [PDF]

				P. Wiesel, A. P. Patel, N. DiFonzo, P. B. Marria, C. U. Sim, A. Pellacani, K. Maemura, B. W. LeBlanc, K. Marino, C. M. Doerschuk, et al. Endotoxin-Induced Mortality Is Related to Increased Oxidative Stress and End-Organ Dysfunction, Not Refractory Hypotension, in Heme Oxygenase-1-Deficient Mice Circulation, December 12, 2000; 102(24): 3015 - 3022. [Abstract] [Full Text] [PDF]

				L. S. Marton, X. Wang, A. Kowalczuk, Z.-D. Zhang, E. Windmeyer, and R. L. Macdonald Effects of hemoglobin on heme oxygenase gene expression and viability of cultured smooth muscle cells Am J Physiol Heart Circ Physiol, November 1, 2000; 279(5): H2405 - H2413. [Abstract] [Full Text] [PDF]

				N. Weissmann, R. Voswinckel, A. Tadic, T. Hardebusch, H. A. Ghofrani, R. T. Schermuly, W. Seeger, and F. Grimminger Nitric Oxide (NO)-Dependent but Not NO-Independent Guanylate Cyclase Activation Attenuates Hypoxic Vasoconstriction in Rabbit Lungs Am. J. Respir. Cell Mol. Biol., August 1, 2000; 23(2): 222 - 227. [Abstract] [Full Text]

				W.-C. Lo, C.-R. Jan, H.-T. Chiang, and C.-J. Tseng Modulatory Effects of Carbon Monoxide on Baroreflex Activation in Nucleus Tractus Solitarii of Rats Hypertension, June 1, 2000; 35(6): 1253 - 1257. [Abstract] [Full Text] [PDF]

				K. A. Nath, J. J. Haggard, A. J. Croatt, J. P. Grande, K. D. Poss, and J. Alam The Indispensability of Heme Oxygenase-1 in Protecting against Acute Heme Protein-Induced Toxicity in Vivo Am. J. Pathol., May 1, 2000; 156(5): 1527 - 1535. [Abstract] [Full Text] [PDF]

				T. R. Grover, R. L. Rairigh, J. P. Zenge, S. H. Abman, and J. P. Kinsella Inhaled carbon monoxide does not cause pulmonary vasodilation in the late-gestation fetal lamb Am J Physiol Lung Cell Mol Physiol, April 1, 2000; 278(4): L779 - L784. [Abstract] [Full Text] [PDF]

				C. Thorup, C. L. Jones, S. S. Gross, L. C. Moore, and M. S. Goligorsky Carbon monoxide induces vasodilation and nitric oxide release but suppresses endothelial NOS Am J Physiol Renal Physiol, December 1, 1999; 277(6): F882 - F889. [Abstract] [Full Text] [PDF]

				W. Durante, K. J. Peyton, and A. I. Schafer Platelet-Derived Growth Factor Stimulates Heme Oxygenase-1 Gene Expression and Carbon Monoxide Production in Vascular Smooth Muscle Cells Arterioscler Thromb Vasc Biol, November 1, 1999; 19(11): 2666 - 2672. [Abstract] [Full Text] [PDF]

				D. M. SUTTNER and P. A. DENNERY Reversal of HO-1 related cytoprotection with increased expression is due to reactive iron FASEB J, October 1, 1999; 13(13): 1800 - 1809. [Abstract] [Full Text]

				C. W. Leffler, A. Nasjletti, C. Yu, R. A. Johnson, A. L. Fedinec, and N. Walker Carbon monoxide and cerebral microvascular tone in newborn pigs Am J Physiol Heart Circ Physiol, May 1, 1999; 276(5): H1641 - H1646. [Abstract] [Full Text] [PDF]

				F. Kozma, R. A. Johnson, F. Zhang, C. Yu, X. Tong, and A. Nasjletti Contribution of endogenous carbon monoxide to regulation of diameter in resistance vessels Am J Physiol Regulatory Integrative Comp Physiol, April 1, 1999; 276(4): R1087 - R1094. [Abstract] [Full Text] [PDF]

				R. C.M. Siow, H. Sato, and G. E. Mann Heme oxygenase-carbon monoxide signalling pathway in atherosclerosis: anti-atherogenic actions of bilirubin and carbon monoxide? Cardiovasc Res, February 1, 1999; 41(2): 385 - 394. [Abstract] [Full Text] [PDF]

				I. J. Benjamin and D. R. McMillan Stress (Heat Shock) Proteins : Molecular Chaperones in Cardiovascular Biology and Disease Circ. Res., July 27, 1998; 83(2): 117 - 132. [Abstract] [Full Text] [PDF]

				R. A. Johnson, E. Colombari, D. S. A. Colombari, M. Lavesa, W. T. Talman, and A. Nasjletti Role of Endogenous Carbon Monoxide in Central Regulation of Arterial Pressure Hypertension, October 1, 1997; 30(4): 962 - 967. [Abstract] [Full Text]

				N. Ishizaka, H. De Leon, J. Bech Laursen, T. Fukui, J. N. Wilcox, G. De Keulenaer, K. K. Griendling, and R. W. Alexander Angiotensin II–Induced Hypertension Increases Heme Oxygenase-1 Expression in Rat Aorta Circulation, September 16, 1997; 96(6): 1923 - 1929. [Abstract] [Full Text]

				J. S. Scheele, V. G. Kharitonov, P. Martasek, L. J. Roman, V. S. Sharma, B. S. S. Masters, and D. Magde Kinetics of CO Ligation with Nitric-oxide Synthase by Flash Photolysis and Stopped-flow Spectrophotometry J. Biol. Chem., May 9, 1997; 272(19): 12523 - 12528. [Abstract] [Full Text] [PDF]

				W. Durante, M. H. Kroll, N. Christodoulides, K. J. Peyton, and A. I. Schafer Nitric Oxide Induces Heme Oxygenase-1 Gene Expression and Carbon Monoxide Production in Vascular Smooth Muscle Cells Circ. Res., April 19, 1997; 80(4): 557 - 564. [Abstract] [Full Text]

				N. Ishizaka and K. K. Griendling Heme Oxygenase-1 Is Regulated by Angiotensin II in Rat Vascular Smooth Muscle Cells Hypertension, March 1, 1997; 29(3): 790 - 795. [Abstract] [Full Text]

				P. J. Lee, B.-H. Jiang, B. Y. Chin, N. V. Iyer, J. Alam, G. L. Semenza, and A. M.K. Choi Hypoxia-inducible Factor-1 Mediates Transcriptional Activation of the Heme Oxygenase-1 Gene in Response to Hypoxia J. Biol. Chem., February 28, 1997; 272(9): 5375 - 5381. [Abstract] [Full Text] [PDF]

				Z.-q. Yan, T. Yokota, W. Zhang, and G. K. Hansson Expression of Inducible Nitric Oxide Synthase Inhibits Platelet Adhesion and Restores Blood Flow in the Injured Artery Circ. Res., July 1, 1996; 79(1): 38 - 44. [Abstract] [Full Text]

				P. Wiesel, L. C. Foster, A. Pellacani, M. D. Layne, C.-M. Hsieh, G. S. Huggins, P. Strauss, S.-F. Yet, and M. A. Perrella Thioredoxin Facilitates the Induction of Heme Oxygenase-1 in Response to Inflammatory Mediators J. Biol. Chem., August 4, 2000; 275(32): 24840 - 24846. [Abstract] [Full Text] [PDF]

				J. S. Robinson, A. L. Fedinec, and C. W. Leffler Role of carbon monoxide in glutamate receptor-induced dilation of newborn pig pial arterioles Am J Physiol Heart Circ Physiol, June 1, 2002; 282(6): H2371 - H2376. [Abstract] [Full Text] [PDF]

				P. Wiesel, A. P. Patel, I. M. Carvajal, Z. Y. Wang, A. Pellacani, K. Maemura, N. DiFonzo, H. G. Rennke, M. D. Layne, S.-F. Yet, et al. Exacerbation of Chronic Renovascular Hypertension and Acute Renal Failure in Heme Oxygenase-1-Deficient Mice Circ. Res., May 25, 2001; 88(10): 1088 - 1094. [Abstract] [Full Text] [PDF]

This Article Abstract Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Christodoulides, N. Articles by Schafer, A. I. Search for Related Content PubMed PubMed Citation Articles by Christodoulides, N. Articles by Schafer, A. I.