β-blockade abolishes the augmented cardiac tPA release induced by transactivation of heterodimerised bradykinin receptor-2 and β2-adrenergic receptor in vivo

2014 ◽  
Vol 112 (11) ◽  
pp. 951-959 ◽  
Author(s):  
Morten Eriksen ◽  
Arnfinn Ilebekk ◽  
Alessandro Cataliotti ◽  
Cathrine Rein Carlson ◽  
Torstein Lyberg ◽  
...  
Keyword(s):  
Adrenergic Receptor ◽  
Sympathetic Nerves ◽  
Ventricular Myocardium ◽  
Left Ventricular ◽  
Left Ventricular Myocardium ◽  
Adrenergic Stimulation ◽  
Β2 Adrenergic Receptor ◽  
Β Blocker

SummaryBradykinin (BK) receptor-2 (B2R) and β2-adrenergic receptor (β2AR) have been shown to form heterodimers in vitro. However, in vivo proofs of the functional effects of B2R-β2AR heterodimerisation are missing. Both BK and adrenergic stimulation are known inducers of tPA release. Our goal was to demonstrate the existence of B2R-β2AR heterodimerisation in myocardium and to define its functional effect on cardiac release of tPA in vivo. We further investigated the effects of a non-selective β-blocker on this receptor interplay. To investigate functional effects of B2R-β2AR heterodimerisation (i. e. BK transactivation of β2AR) in vivo, we induced serial electrical stimulation of cardiac sympathetic nerves (SS) in normal pigs that underwent concomitant BK infusion. Both SS and BK alone induced increases in cardiac tPA release. Importantly, despite B2R desensitisation, simultaneous BK infusion and SS (BK+SS) was characterised by 2.3 ± 0.3-fold enhanced tPA release compared to SS alone. When β-blockade (propranolol) was introduced prior to BK+SS, tPA release was inhibited. A persistent B2R-β2AR heterodimer was confirmed in BK-stimulated and nonstimulated left ventricular myocardium by immunoprecipitation studies and under non-reducing gel conditions. All together, these results strongly suggest BK transactivation of β2AR leading to enhanced β2AR-mediated release of tPA. Importantly, non-selective β-blockade inhibits both SS-induced release of tPA and the functional effects of B2R-β2AR heterodimerisation in vivo, which may have important clinical implications.

Reductions of myocardial Na-K-ATPase activity and ouabain binding sites in heart failure: prevention by nadolol

1993 ◽  
Vol 265 (6) ◽  
pp. H2086-H2093 ◽  
Author(s):  
T. H. Fan ◽  
R. P. Frantz ◽  
H. Elam ◽  
S. Sakamoto ◽  
N. Imai ◽  
...  
Keyword(s):  
Heart Failure ◽  
Atpase Activity ◽  
Binding Sites ◽  
Early Stage ◽  
Ventricular Myocardium ◽  
Left Ventricular ◽  
Left Ventricular Myocardium ◽  
Adrenergic Stimulation ◽  
Ouabain Binding ◽  
Systemic Hemodynamic

To study the changes in myocardial digitalis binding sites in heart failure, we measured myocardial ouabain binding sites, Na-K-adenosinetriphosphatase (ATPase) activity, and ventricular muscle mechanical responses to acetylstrophanthidin in dogs with right-heart failure (RHF) produced by tricuspid avulsion and pulmonary artery constriction. Sham-operated dogs were studied as the control. RHF produced a significant decrease in ouabain binding sites in the right and left ventricular myocardium, which was accompanied by a proportional decrease in Na-K-ATPase activity. However, RHF and sham-operated dogs did not differ in systemic hemodynamic or right ventricular trabeculate muscle isometric contractile responses to acetylstrophanthidin. To determine whether chronic beta-adrenergic stimulation contributed to the development of Na-K-ATPase downregulation, we administered nadolol (40 mg/day) to a separate group of dogs during an early stage of RHF development. Nadolol effectively prevented the reduction of myocardial ouabain binding sites that occurred in RHF. Thus we conclude that myocardial ouabain binding sites and Na-K-ATPase activity are reduced in dogs with experimental heart failure and that these changes probably occur as a result of the attendant heightened sympathetic activity.

Cardiac microdialysis in isolated rat hearts: interstitial purine metabolites during ischemia

1992 ◽  
Vol 262 (6) ◽  
pp. H1934-H1938 ◽  
Author(s):  
D. G. Van Wylen ◽  
T. J. Schmit ◽  
R. D. Lasley ◽  
R. L. Gingell ◽  
R. M. Mentzer
Keyword(s):  
Uric Acid ◽  
Ventricular Myocardium ◽  
Left Ventricular ◽  
Left Ventricular Myocardium ◽  
Isolated Perfused Heart ◽  
Perfused Heart ◽  
Purine Metabolites ◽  
Valuable Adjunct ◽  
Rat Hearts

Cardiac microdialysis is a recently developed technique that allows intramyocardial interstitial fluid (ISF) to be sampled via the implantation and perfusion of a small, hollow dialysis fiber within the myocardium. The purpose of this paper is to describe initial studies using cardiac microdialysis in the isolated perfused heart. Microdialysis probes, constructed in the laboratory, were implanted in the left ventricular myocardium of isolated perfused rat hearts and perfused at 0.5 microliter/min with Krebs-Henseleit buffer. The effluent dialysate, assayed for adenosine, inosine, hypoxanthine, xanthine, and uric acid, was used as an index of intramyocardial levels of these purine metabolites. All metabolites were elevated initially after implantation, declined rapidly in the first 45 min, and were then stable for the next 90 min. Based on in vitro percent recovery data, baseline dialysate concentrations were extrapolated to yield estimates of intramyocardial ISF (in microM) 0.47 adenosine, 0.85 inosine, 0.29 hypoxanthine, 0.49 xanthine, and 8.6 uric acid. During global zero-flow ischemia (37 degrees C), dialysate levels of all purine metabolites were elevated, with inosine being the predominant compound. Pretreatment of the hearts with 50 microM erythro-9-(2-hydroxy-3-nonyl)adenine, an adenosine deaminase inhibitor, markedly enhanced ISF adenosine accumulation and attenuated the accumulation of inosine, hypoxanthine, and xanthine. The simplicity and versatility of cardiac microdialysis in the isolated perfused heart suggest that this technique may be a valuable adjunct to the many studies performed using this preparation.

scholarly journals MO330ACTIVATION OF Β2 ADRENERGIC RECEPTOR SIGNALING IN MACROPHAGES BLOCKS SYSTEMIC INFLAMMATION AND PROTECTS AGAINST RENAL ISCHEMIA/REPERFUSION INJURY

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Sho Hasegawa ◽  
Tsuyoshi Inoue ◽  
Masaomi Nangaku ◽  
Reiko Inagi
Keyword(s):  
Rna Sequencing ◽  
Systemic Inflammation ◽  
Adrenergic Receptor ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Renal Tissue ◽  
Β2 Adrenergic Receptor ◽  
Anti Inflammatory

Abstract Background and Aims The sympathetic nervous system regulates immune cell dynamics. However, the detailed role of sympathetic signaling in inflammatory diseases is still unclear because it varies according to the disease situation and responsible cell types. Here, we focused on sympathetic signaling in macrophages and sought to determine its detailed roles in lipopolysaccharide (LPS)-induced systemic inflammation and renal ischemia/reperfusion injury (IRI). Method In vitro, RAW 264.7 cells and murine peritoneal macrophages were used to determine the effects of β2 adrenergic receptor (Adrb2) signaling on LPS-induced proinflammatory cytokine (tumor necrosis factor-α; TNF-α) production. We also identified the critical gene that mediates the anti-inflammatory effect of Adrb2 signaling by RNA-sequencing. In vivo, we examined the effects of salbutamol (a selective Adrb2 agonist) in LPS-induced systemic inflammation and renal IRI. The involvement of macrophage Adrb2 signaling was confirmed by macrophage-specific Adrb2 conditional knockout (cKO) mice and adoptive transfer of salbutamol-treated macrophages. We also performed single-cell RNA sequencing of renal tissue to analyze the renoprotective role of salbutamol-treated macrophages in detail. Results In vitro, norepinephrine, a sympathetic neurotransmitter, suppressed LPS-induced TNF-α production in macrophages. This anti-inflammatory effect was also induced by salbutamol and reversed by butoxamine (a selective Adrb2 antagonist) in a dose-dependent manner, indicating the importance of Adrb2 in this process. RNA sequencing of these macrophages revealed that T-cell immunoglobulin and mucin-3 (Tim3) expressions were upregulated by the activation of Adrb2 signaling, which partially mediated the anti-inflammatory phenotypic alteration in macrophages. In vivo, salbutamol administration mitigated LPS-induced systemic inflammation and protected against renal IRI; this protection was mitigated in macrophage-specific Adrb2 cKO mice. Adoptive transfer of salbutamol-treated macrophages also protected against renal IRI (Figure 1). Single-cell RNA sequencing revealed that this protection was associated with the accumulation of Tim3-expressing macrophages in the renal tissue. Conclusion The activation of β2 adrenergic receptor signaling in macrophages induces anti-inflammatory phenotypic alterations partially via the induction of Tim3 expressions, which blocks LPS-induced systemic inflammation and protects against renal IRI.

Immuno-Enzyme Histochemistry of Creatine Phosphokinase

1977 ◽  
Vol 35 ◽  
pp. 446-447
Author(s):  
N. Baba ◽  
E.T. Poe ◽  
J. Scillian ◽  
T. Myser
Keyword(s):  
Creatine Phosphokinase ◽  
Ventricular Myocardium ◽  
Left Ventricular ◽  
Left Ventricular Myocardium ◽  
Rabbit Muscle ◽  
Cytoplasmic Staining ◽  
Heart Muscle Cells ◽  
Diffuse Cytoplasmic Staining ◽  
Strong Staining

With a commercially available rabbit muscle (MM) type isoenzyme of the creatine phosphokinase (CPK) (Worthington Biochemical), anti-CPK antibody was produced in chicken and goat (Figure 1). Fab' fragments of the chicken and goat IgG were isolated and conjugated with a commercially available horseradish peroxidase (HRP) according to the Nakane method (J. Histochem. Cytochem,, 22:1084, 1974).Rabbit hearts were perfused in vivo with freshly prepared 2% paraformaldehyde solution, and the left ventricular myocardium was fixed for 30 minutes. Forty-micrometer-thick frozen sections of the myocardium were incubated with the Fab'-HRP conjugate overnight at 4°C. After a thorough rinse, the sections were stained for the peroxidase reaction.In an electron microscope, diffuse cytoplasmic staining of the heart muscle cells was noted, indicating the diffuse cytosol distribution of CPK (Figure 2). In addition, there was strong staining of the intermembranous and intracristal space of the mitochondria as well as the M-lines of the myofibrils (Figures 3 and 4).

In vivo detection of endogenous acetylcholine release in cat ventricles

1994 ◽  
Vol 266 (3) ◽  
pp. H854-H860 ◽  
Author(s):  
T. Akiyama ◽  
T. Yamazaki ◽  
I. Ninomiya
Keyword(s):  
Nerve Stimulation ◽  
Ventricular Myocardium ◽  
Left Ventricular ◽  
Vagal Nerve ◽  
Vagal Nerve Stimulation ◽  
Left Ventricular Myocardium ◽  
Ach Release ◽  
Vagal Nerves ◽  
Dialysis Technique

To detect and monitor endogenous acetylcholine (ACh) release in the in vivo heart, we applied a dialysis technique to the hearts of anesthetized cats. Dialysis probes were implanted in the left ventricular myocardium and were perfused with Krebs-Henseleit solution containing Eserine (10(-4) M) at 3 microliters/min. Dialysate ACh concentration was measured with high-performance liquid chromatography. In four cats, the response to vagal stimulation was studied. Electrical stimulation of efferent vagal nerves (10 Hz) significantly increased dialysate ACh concentration from 596 +/- 118 (control) to 12,210 +/- 1,661 pM. After stimulation, dialysate ACh concentration significantly decreased to 382 +/- 80 pM below control. The influence of ganglionic blocker was determined in six cats. Control vagal nerve stimulation (10 Hz) increased dialysate ACh concentration from 582 +/- 136 to 9,102 +/- 754 pM. Local perfusion of hexamethonium (10(-4) M) did not affect this nerve stimulation-induced ACh increase (8,611 +/- 1,189 pM), and intravenous administration of hexamethonium (20 mg/kg) prevented this increase (340 +/- 88 pM). We examined the response to vagal nerve stimulation at different frequencies in three cats. Vagal nerve stimulation increased dialysate ACh concentration from a control of 588 +/- 211 to 1,227 +/- 195 pM at 2 Hz, 3,946 +/- 1,059 pM at 5 Hz, and 9,366 +/- 1,873 pM at 10 Hz. Dialysate ACh concentration reflects ACh release from postganglionic vagal nerves innervating the left ventricular myocardium; the dialysis technique permits estimation of relative changes in efferent cardiac vagal nerve activity.

scholarly journals β2-Adrenergic Receptor Signaling in Osteoblasts Contributes to the Catabolic Effect of Glucocorticoids on Bone

Endocrinology ◽  
2011 ◽  
Vol 152 (4) ◽  
pp. 1412-1422 ◽  
Author(s):  
Yun Ma ◽  
Jeffry S. Nyman ◽  
Huan Tao ◽  
Heather H. Moss ◽  
Xiangli Yang ◽  
...  
Keyword(s):  
Bone Loss ◽  
Bone Cells ◽  
Sympathetic Nerves ◽  
Bone Diseases ◽  
Autonomic Nerves ◽  
High Dose ◽  
Bone Homeostasis ◽  
Adrenergic Stimulation

Abstract The sympathetic nervous system is a physiological regulator of bone homeostasis. Autonomic nerves are indeed present in bone, bone cells express the β2-adrenergic receptors (β2AR), and pharmacological or genetic disruption of sympathetic outflow to bone induces bone gain in rodents. These recent findings implied that conditions that affect β2AR signaling in osteoblasts and/or sympathetic drive to bone may contribute to bone diseases. In this study, we show that dexamethasone stimulates the expression of the β2AR in differentiated primary calvarial osteoblasts, as measured by an increase in Adrβ2 mRNA and β2AR protein level after short-term dexamethasone treatment. Isoproterenol-induced cAMP accumulation and the expression of the β2AR target gene Rankl were also significantly increased after dexamethasone pretreatment, indicating that dexamethasone promotes the responsiveness of differentiated osteoblasts to adrenergic stimulation. These in vitro results led to the hypothesis that glucocorticoid-induced bone loss, provoked by increased endogenous or high-dose exogenous glucocorticoids given for the treatment of inflammatory diseases, might, at least in part, be mediated by increased sensitivity of bone-forming cells to the tonic inhibitory effect of sympathetic nerves on bone formation or their stimulatory effect on bone resorption. Supporting this hypothesis, both pharmacological and genetic β2AR blockade in mice significantly reduced the bone catabolic effect of high-dose prednisolone in vivo. This study emphasizes the importance of sympathetic nerves in the regulation of bone homeostasis and indicates that this neuroskeletal signaling axis can be modulated by hormones or drugs and contribute to enhance pathological bone loss.

Effect of postburn serum on in vitro respiration of normal myocardium

1963 ◽  
Vol 18 (4) ◽  
pp. 821-823 ◽  
Author(s):  
Arthur A. Spector
Keyword(s):  
Fatty Acids ◽  
Oxygen Consumption ◽  
Technical Assistance ◽  
Ventricular Myocardium ◽  
Left Ventricular ◽  
Left Ventricular Myocardium ◽  
Burn Shock ◽  
Cardiac Defect ◽  
Electrophoretic Patterns

An in vitro respiratory system using normal guinea pig left ventricular myocardium is described. QO2 values are given for this preparation incubated with representative substrates. A larger elevation in oxygen consumption is seen with linoleic acid as compared to other unesterified fatty acids tested. Serum obtained from dogs before and 15 min after flash burn was incubated with this heart slice system. No differences in oxygen uptake are noted between addition of control and postburn serum. No major serum enzymatic or chemical alterations are found at 15 min postburn. Plasma protein electrophoretic patterns remain unchanged at 15 and 40 min after injury. These results do not support the concept that the cardiac defect in early burn shock is caused by a circulating substance that either inhibits oxidation or uncouples oxidative phosphorylation by the myocardium. Note: (With the Technical Assistance of Ralph A. Abreo and Raburn Jackson) Submitted on November 15, 1962

Deficiency in endothelial nitric oxide synthase impairs myocardial angiogenesis

2002 ◽  
Vol 283 (6) ◽  
pp. H2371-H2378 ◽  
Author(s):  
Xue Zhao ◽  
Xiangru Lu ◽  
Qingping Feng
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Heart Development ◽  
Tube Formation ◽  
Left Ventricular ◽  
Left Ventricular Myocardium ◽  
Wild Type ◽  
Endothelial Nitric Oxide

We recently demonstrated that mice deficient in endothelial nitric oxide (NO) synthase (eNOS) have congenital septal defects and postnatal heart failure. However, the mechanisms by which eNOS affects heart development are not clear. We hypothesized that deficiency in eNOS impairs myocardial angiogenesis. Myocardial capillary densities were measured morphometrically in neonatal mouse hearts. In vitro tube formation on Matrigel was investigated in cardiac endothelial cells. In vivo myocardial angiogenesis was performed by implanting Matrigel in the left ventricular myocardium. Myocardial capillary densities and VEGF mRNA expression were decreased in neonatal eNOS−/− compared with neonatal wild-type mice ( P < 0.01). Furthermore, in vitro tube formation from cardiac endothelial cells and in vivo myocardial angiogenesis were attenuated in eNOS−/− compared with wild-type mice ( P < 0.01). In vitro tube formation was inhibited by N G-nitro-l-arginine methyl ester in wild-type mice and restored by a NO donor, diethylenetriamine-NO, in eNOS−/− mice ( P < 0.05). In conclusion, deficiency in eNOS decreases VEGF expression and impairs myocardial angiogenesis and capillary development. Decreased myocardial angiogenesis may contribute to cardiac abnormalities during heart development in eNOS−/− mice.

Impact of acute and enduring volume overload on mechanotransduction and cytoskeletal integrity of canine left ventricular myocardium

2007 ◽  
Vol 292 (5) ◽  
pp. H2324-H2332 ◽  
Author(s):  
Dirk W. Donker ◽  
Jos G. Maessen ◽  
Fons Verheyen ◽  
Frans C. Ramaekers ◽  
Roel L. H. M. G. Spätjens ◽  
...  
Keyword(s):  
Protein Expression ◽  
Volume Overload ◽  
Ventricular Myocardium ◽  
Left Ventricular ◽  
Left Ventricular Myocardium ◽  
Mechanical Stimuli ◽  
Hypertrophic Growth ◽  
Lim Protein ◽  
Ventricular Mechanics

It is poorly understood how mechanical stimuli influence in vivo myocardial remodeling during chronic hemodynamic overload. Combined quantitation of ventricular mechanics and expression of key proteins involved in mechanotransduction can improve fundamental understanding. Adult anesthetized dogs ( n = 20) were studied at sinus rhythm (SR) and 0, 3, 10, and 35 days of complete atrioventricular block (AVB). Serial left ventricular (LV) myofiber mechanics were measured. Repeated LV biopsies were analyzed for mRNA and/or protein expression of β1D-integrin, melusin, Akt, GSK3β, muscle LIM protein (MLP), four-and-a-half LIM protein 2 (fhl2), desmin, and calpain. Upon AVB, increased ejection strain (0.29 ± 0.01 vs. 0.13 ± 0.02, SR) and end-diastolic stress (4.8 ± 1.1 vs. 2.7 ± 0.4 kPa) dominated mechanical changes. Brain natriuretic peptide plasma levels were correspondingly high (33 ± 4 vs. 19 ± 1 pg/ml, SR). β1D-Integrin protein expression increased chronically after AVB. Melusin was temporarily overexpressed (+33 ± 9%, 3 days AVB vs. SR), followed by elevated ratios of phosphorylated (P)-Akt to Akt and P-GSK3β to GSK3β (+26 ± 6% and +30 ± 8% at 10 days AVB vs. SR). These changes corresponded to peak hypertrophic growth at 3 to 10 days. MLP increased gradually to maxima at chronic AVB (+36 ± 7%). In contrast, fhl2 (−22 ± 3%, 3 days) and desmin (−30 ± 9%, 10 days AVB) transiently declined but recovered at chronic AVB. Calpain protein expression remained unaltered. In conclusion, volume overload after AVB causes a transient compromise of cytoskeletal integrity based, at least partly, on transcriptional downregulation. Subsequent cytoskeletal reorganization coincides with the upregulation of melusin, P-Akt, P-GSK3β, and MLP, indicating a strong drive to compensated hypertrophy.

Silencing of NHE-1 blunts the slow force response to myocardial stretch

2011 ◽  
Vol 111 (3) ◽  
pp. 874-880 ◽  
Author(s):  
Néstor G. Pérez ◽  
Mariela B. Nolly ◽  
Mirian C. Roldan ◽  
María C. Villa-Abrille ◽  
Eugenio Cingolani ◽  
...  
Keyword(s):  
Lentiviral Vector ◽  
Ventricular Myocardium ◽  
Left Ventricular ◽  
Left Ventricular Myocardium ◽  
Force Response ◽  
Rapid Phase ◽  
Key Factor ◽  
Myocardial Stretch ◽  
And Function

Myocardial stretch induces a biphasic force response: a first abrupt increase followed by a slow force response (SFR), believed to be the in vitro manifestation of the Anrep effect. The SFR is due to an increase in Ca2+ transient of unclear mechanism. We proposed that Na+/H+ exchanger (NHE-1) activation is a key factor in determining the contractile response, but recent reports challenged our findings. We aimed to specifically test the role of the NHE-1 in the SFR. To this purpose small hairpin interference RNA capable of mediating specific NHE-1 knockdown was incorporated into a lentiviral vector (l-shNHE1) and injected into the left ventricular wall of Wistar rats. Injection of a lentiviral vector expressing a nonsilencing sequence (scramble) served as control. Myocardial NHE-1 protein expression and function (the latter evaluated by the recovery of pHi after an acidic load and the SFR) were evaluated. Animals transduced with l-shNHE1 showed reduced NHE-1 expression (45 ± 8% of controls; P < 0.05), and the presence of the lentivirus in the left ventricular myocardium, far from the site of injection, was evidenced by confocal microscopy. These findings correlated with depressed basal pHi recovery after acidosis [maxdpHi/d t 0.055 ± 0.008 (scramble) vs. 0.009 ± 0.004 (l-shNHE1) pH units/min, P < 0.05], leftward shift of the relationship between JH+ (H+ efflux corrected by the intrinsic buffer capacity), and abolishment of SFR (124 ± 2 vs. 101 ± 2% of rapid phase; P < 0.05) despite preserved ERK1/2 phosphorylation [247 ± 12 (stretch) and 263 ± 23 (stretch l-shNHE1) % of control; P < 0.05 vs. nonstretched control], well-known NHE-1 activators. Our results provide strong evidence to propose NHE-1 activation as key factor in determining the SFR to stretch.

Sign in / Sign up

Export Citation Format

Share Document