Heme oxygenase activity in the adult rat aorta and liver as measured by carbon monoxide formation

1995 ◽  
Vol 73 (4) ◽  
pp. 515-518 ◽  
Author(s):  
Michael N. Cook ◽  
Kanji Nakatsu ◽  
Gerald S. Marks ◽  
Brian E. McLaughlin ◽  
Hendrik J. Vreman ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Heme Oxygenase ◽  
Rat Liver ◽  
Physiological Role ◽  
Rat Aorta ◽  
Supernatant Fraction ◽  
Smooth Muscle Relaxation ◽  
Aortic Tissue

Rat aorta was homogenized and the 13 000 × g supernatant fraction was tested for heme oxygenase (HO) activity by using a sensitive gas chromatographic method to measure carbon monoxide (CO), one of the products of the HO reaction. The rate of NADPH-dependent CO formation, an index of HO activity, was 1.41 ± 0.40 nmol CO∙mg−1 protein∙h−1 in the rat aorta supernatant fraction and 2.05 ± 0.55 nmol CO∙mg−1 protein∙h−1 in the rat liver 13 000 × g supernatant fraction, a tissue known to contain HO activity. Chromium mesoporphyrin (0.05 mM), an inhibitor of rat liver HO, significantly decreased HO activity by 26% in the aorta supernatant fraction and 50% in the liver supernatant fraction. On the basis of the results of this study, which demonstrated HO-catalyzed CO formation in aortic tissue, and previous observations that CO relaxes vascular smooth muscle, we suggest that a physiological role for CO in vascular smooth muscle relaxation should be further investigated.Key words: carbon monoxide, heme oxygenase, vascular smooth muscle, liver, gas chromatographic analysis.

An extracellular source of heme can induce a significant heme oxygenase mediated relaxation in the rat aorta

2002 ◽  
Vol 80 (8) ◽  
pp. 761-765 ◽  
Author(s):  
S Hosein ◽  
G S Marks ◽  
J F Brien ◽  
B E McLaughlin ◽  
K Nakatsu
Keyword(s):  
Carbon Monoxide ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Blood Vessels ◽  
Vascular Smooth Muscle Cells ◽  
Heme Oxygenase ◽  
Muscle Cells ◽  
Rat Aorta ◽  
Bathing Medium

Carbon monoxide has been under active investigation for a role in controlling vascular tone throughout the last decade because of its ability to induce relaxation in blood vessels. The underlying mechanisms of this response are hypothesized to be mediated by soluble guanylyl cyclase (sGC) and, in some instances, KCa channels. The major source of CO in major blood vessels is the catabolic process of heme degradation, which is catalyzed by heme oxygenase (HO). This heme substrate could be derived from heme sources within vascular smooth muscle cells, such as heme proteins, or by uptake from the extracellular milieu. The current study shows that the isolated rat aorta relaxes upon exposure to pharmacological concentrations of heme in the bathing medium. This response was inhibited by an inhibitor of HO (tin protoporphyrin) and sGC (1-H-[1,2,4]-oxadiazolo[4,3-a]quinoxalin-1-one). These observations were interpreted to mean that vascular smooth muscle cells are capable of taking up and utilizing heme for the production of CO. Key words: carbon monoxide, heme oxygenase, heme, vascular smooth muscle.

scholarly journals EVALUATION OF IN-VITRO VASORELAXANT EFFECT (POTENTIAL ANTIHYPERTENSIVE) OF KIGELIA AFRICANA FRUIT METHANOL EXTRACT ON POTASSIUM CHLORIDE AND PHENYLEPHRINE INDUCED TENSION IN WISTAR RAT AORTA

2020 ◽  
Vol 4 (3) ◽  
pp. 470-475
Author(s):  
A. O. Isah ◽  
M. Idu ◽  
A. A. Abdulrahman ◽  
F. Amaechina
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Potassium Chloride ◽  
Methanol Extract ◽  
Muscle Relaxation ◽  
Rat Aorta ◽  
Smooth Muscle Relaxation ◽  
Organ Bath ◽  
Vasorelaxant Effect

This research on Kigelia africana was conducted in order to ascertain its ability to relax excited vascular smooth muscle in rat aorta. Preliminary investigation on whether the plant exhibits antihypertensive property was done before the evaluation of in vitro vasorelaxant effect. The vasorelaxant activity was determined using in vitro method on rat aorta with the aid of perfusion apparatus with a detachable organ bath. The administration of potassium chloride (KCl) raised the tension from 1.0 to 1.31 indicating that the aorta got to its peak of contraction. At 10 and 20mg/kg, the tension dropped significantly, showing relaxation of the smooth muscle while at 5mg/kg, drop in tension was insignificant at p˂0.05. However, at some of the doses, towards the end of experiment, there was steady resurge in tension showing that the aorta resumed contraction. On the application of phenylephrine (PE), the tension rose to 1.18g. On administration of the extract, the tension dropped slightly showing mild vascular smooth muscle relaxation. From the results obtained, there was seeming similarity in the action of the K. africana compared to amlodipine/Ramipril in KCl and PE induced tension in aorta respectively. However, at 10 and 20mg/kg, a substantial decrease in tension was noted indicating that the extract action is dose dependent. Thus, from this in-vitro smooth muscle relaxation study in rats, the methanol extract of K. africana has depressant property that was likely expressed by enhancing the closing of voltage operated calcium channel and ACE inhibiting activity in KCl and Phenylephrine induced tension respectively.

Decline in caveolin-1 expression and scaffolding of G protein receptor kinase-2 with age in Fischer 344 aortic vascular smooth muscle

2005 ◽  
Vol 288 (5) ◽  
pp. H2457-H2464 ◽  
Author(s):  
William E. Schutzer ◽  
John F. Reed ◽  
Scott L. Mader
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
G Protein ◽  
Rat Aorta ◽  
Lower Percentage ◽  
Aortic Tissue ◽  
Receptor Kinase ◽  
Caveolin 1 ◽  
Fischer 344 ◽  
Protein Receptor

β-Adrenergic receptor (β-AR)-mediated vasorelaxation declines with age in humans and animal models. This is not caused by changes in expression of β-AR, Gαs, adenylyl cyclase, or protein kinase A but is associated with decreased cAMP production. Expression and activity of G protein receptor kinase-2 (GRK-2), which phosphorylates and desensitizes the β-AR, increases with age in rat aortic tissue. Caveolin scaffolds the β-AR, GRK, and other proteins within “signaling pockets” and inhibits GRK activity when bound. We questioned the effect of age on caveolin-1 expression and interaction between caveolin-1 and GRK-2 in vascular smooth muscle (VSM) isolated from 2-, 6-, 12-, and 24-mo-old male Fischer 344 rat aorta. Western blot analysis found expression of caveolin-1 declined with age (6-, 12- and 24-mo-old rat aortas express 92, 50, and 42% of 2-mo-old rat aortas, respectively). Results from density-buoyancy analysis showed a lower percentage of GRK in caveolin-1-specific fractions with age (6-, 12- and 24-mo-old rat aortas express 95, 56, and 12% of 2-mo-old rat aortas, respectively). Coimmunoprecipitation confirmed this finding; density of GRK in caveolin-1 immunoprecipitates was 97, 30, and 21% of 2-mo-old aortas compared with 6-, 12- and 24-mo-old animals, respectively. Immunohistocytochemistry and confocal microscopy confirmed that GRK-2 and caveolin-1 colocalize in VSM. These results suggest that in nonoverexpressed, intact tissue, the decline in β-AR-mediated vasorelaxation may be caused by both a reduction in caveolin-1 expression and a reduction in binding of GRK-2 by caveolin-1. This could lead to an increase in the fraction of free GRK-2, which could phosphorylate and desensitize the β-AR.

Nitric Oxide Induces Heme Oxygenase-1 Gene Expression and Carbon Monoxide Production in Vascular Smooth Muscle Cells

1997 ◽  
Vol 80 (4) ◽  
pp. 557-564 ◽  
Author(s):  
William Durante ◽  
Michael H. Kroll ◽  
Nick Christodoulides ◽  
Kelly J. Peyton ◽  
Andrew I. Schafer
Keyword(s):  
Gene Expression ◽  
Nitric Oxide ◽  
Carbon Monoxide ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Heme Oxygenase ◽  
Muscle Cells ◽  
Heme Oxygenase 1

Heme oxygenase-1–derived carbon monoxide is an autocrine inhibitor of vascular smooth muscle cell growth

Blood ◽  
2002 ◽  
Vol 99 (12) ◽  
pp. 4443-4448 ◽  
Author(s):  
Kelly J. Peyton ◽  
Sylvia V. Reyna ◽  
Gary B. Chapman ◽  
Diana Ensenat ◽  
Xiao-ming Liu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Carbon Monoxide ◽  
Smooth Muscle ◽  
Cell Growth ◽  
Vascular Smooth Muscle ◽  
Dna Synthesis ◽  
Heme Oxygenase ◽  
Cyclin A ◽  
Heme Oxygenase 1 ◽  
Vascular Smcs

Vascular smooth muscle cells (SMCs) generate carbon monoxide (CO) via the catabolism of heme by the enzyme heme oxygenase (HO). In the present study, we found that serum stimulated a time- and concentration-dependent increase in the levels of HO-1 messenger RNA (mRNA) and protein in vascular SMCs. The induction of HO-1 expression by serum was inhibited by actinomycin D or cycloheximide. In addition, serum stimulated HO activity, as reflected by an increase in the concentration of bilirubin in the culture media. Treatment of vascular SMCs with serum stimulated DNA synthesis and this was potentiated by the HO inhibitors, zinc and tin protoporphyrin-IX as well as by the CO scavenger, hemoglobin. The iron chelator desferrioxamine had no effect on DNA synthesis. However, exposure of vascular SMCs to exogenous CO inhibited serum-stimulated SMC proliferation and the phosphorylation of retinoblastoma protein. In addition, CO arrested SMCs at the G1/S transition phase of the cell cycle and selectively blocked the serum-stimulated expression of cyclin A mRNA and protein without affecting the expression of cyclin D1 and E. CO also inhibited the serum-stimulated activation of cyclin A–associated kinase activity and cyclin-dependent kinase 2 activity. These results demonstrate that serum stimulates HO-1 gene expression and CO synthesis. Furthermore, they show that CO acts in a negative feedback fashion to inhibit vascular SMC growth by regulating specific components of the cell cycle machinery. The capacity of vascular mitogens to induce CO synthesis may provide a novel mechanism by which these agents modulate cell growth.

cAMP induces heme oxygenase-1 gene expression and carbon monoxide production in vascular smooth muscle

1997 ◽  
Vol 273 (1) ◽  
pp. H317-H323 ◽  
Author(s):  
W. Durante ◽  
N. Christodoulides ◽  
K. Cheng ◽  
K. J. Peyton ◽  
R. K. Sunahara ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Heme Oxygenase ◽  
Muscle Cells ◽  
Heme Oxygenase 1 ◽  
Zinc Protoporphyrin ◽  
Intracellular Camp

Recent studies indicate that vascular smooth muscle cells generate carbon monoxide (CO) via the action of heme oxygenase (HO). Because adenosine 3',5'-cyclic monophosphate (cAMP) is an important intracellular signaling molecule in the regulation of vascular cell function, we examined whether this second messenger modulates the expression of HO and the production of CO by rat aortic smooth muscle cells. Treatment of smooth muscle cells with the membrane-permeable cAMP derivative dibutyryl cAMP or with compounds that increase intracellular cAMP levels (isoproterenol and forskolin) resulted in a concentration- and time-dependent increase in the levels of HO-1 mRNA and protein, whereas the expression of HO-2 remained unchanged. Both actinomycin D and cycloheximide blocked the basal expression of HO-1 mRNA and protein and prevented the cAMP-mediated induction of HO-1. Incubation of platelets with cAMP-treated smooth muscle cells resulted in a significant increase in platelet cGMP concentration that was partially reversed by treatment of smooth muscle cells with the nitric oxide synthase inhibitor NG-monomethyl-L-arginine or the HO blocker zinc protoporphyrin-IX. However, the combined addition of these two inhibitors to cAMP-treated smooth muscle cells or the addition of the CO and NO scavenger hemoglobin to platelets completely blocked the stimulatory effect on platelet cGMP levels. These results demonstrate that cAMP induces the expression of the HO-1 gene and stimulates the formation of CO and NO in vascular smooth muscle cells. The capacity of cAMP to induce the synthesis of guanylate cyclase-stimulatory CO from smooth muscle cells may represent a novel mechanism by which this nucleotide regulates vascular tone.

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