scholarly journals Phosphodiesterases 2, 3 and 4 can decrease cardiac effects of H2-histamine-receptor activation in isolated atria of transgenic mice

2021 ◽  
Author(s):  
Joachim Neumann ◽  
Rafaela Voss ◽  
Ulrich Laufs ◽  
Christian Werner ◽  
Ulrich Gergs
Keyword(s):  
Transgenic Mice ◽  
Histamine Receptor ◽  
Receptor Activation ◽  
Heart Beat ◽  
Right Atrial ◽  
Pde4 Inhibitor ◽  
Inotropic Effects ◽  
Pde Inhibitors ◽  
Isolated Atria ◽  
Left And Right

AbstractHistamine exerts cAMP-dependent positive inotropic effects (PIE) and positive chronotropic effects (PCE) on isolated left and right atria, respectively, of transgenic mice which overexpress the human H2-receptor in the heart (=H2-TG). To determine whether these effects are antagonized by phosphodiesterases (PDEs), contractile studies were done in isolated left and right atrial preparations of H2-TG. The contractile effects of histamine were tested in the additional presence of the PDE-inhibitorserythro-9-(2-hydroxy-3-nonyl)adenine hydrochloride (EHNA, 1 μM, PDE2-inhibitor) or cilostamide (1 μM, PDE3-inhibitor), rolipram (10 μM, a PDE4-inhibitor), and their combinations. Cilostamide (1 μM) and EHNA (1 μM), rolipram (1 μM), and EHNA (1 μM) and the combination of rolipram (0.1 μM) and cilostamide (1 μM) each increased the potency of histamine to elevate the force of contraction (FOC) in H2-TG. Cilostamide (1 μM) and rolipram (10 μM) alone increased and EHNA (1 μM) decreased alone, and their combination increased the potency of histamine to increase the FOC in H2-TG indicating that PDE3 and PDE4 regulate the inotropic effects of histamine in H2-TG. The PDE inhibitors (EHNA, cilostamide, rolipram) alone did not alter the potency of histamine to increase the heart beat in H2-TG whereas a combination of rolipram, cilostamide, and EHNA, or of rolipram and EHNA increased the potency of histamine to act on the beating rate. In summary, the data suggest that the PCE of histamine in H2-TG atrium involves PDE 2 and 4 activities, whereas the PIE of histamine are diminished by activity of PDE 3 and 4.

scholarly journals Amitriptyline functionally antagonizes cardiac H2 histamine receptors in transgenic mice and human atria

2021 ◽  
Author(s):  
Joachim Neumann ◽  
Maximilian Benedikt Binter ◽  
Charlotte Fehse ◽  
Margaréta Marušáková ◽  
Maren Luise Büxel ◽  
...  
Keyword(s):  
Antidepressant Drug ◽  
Histamine Receptor ◽  
Right Atrial ◽  
Inotropic Effects ◽  
Positive Inotropic Effects ◽  
Contractile Parameters ◽  
Left And Right ◽  
Chronotropic Effects ◽  
Perfused Hearts ◽  
Right Atria

AbstractWe have previously shown that histamine (2-(1H-imidazol-4-yl)ethanamine) exerted concentration-dependent positive inotropic effects (PIE) or positive chronotropic effects (PCE) on isolated left and right atria, respectively, of transgenic (H2R-TG) mice that overexpress the human H2 histamine receptor (H2R) in the heart; however, the effects were not seen in their wild-type (WT) littermates. Amitriptyline, which is still a highly prescribed antidepressant drug, was reported to act as antagonist on H2Rs. Here, we wanted to determine whether the histamine effects in H2R-TG were antagonized by amitriptyline. Contractile studies were performed on isolated left and right atrial preparations, isolated perfused hearts from H2R-TG and WT mice and human atrial preparations. Amitriptyline shifted the concentration-dependent PIE of histamine (1 nM–10 μM) to higher concentrations (rightward shift) in left atrial preparations from H2R-TG. Similarly, in isolated perfused hearts from H2R-TG and WT mice, histamine increased the contractile parameters and the phosphorylation state of phospholamban (PLB) at serine 16 in the H2R-TG mice, but not in the WT mice. However, the increases in contractility and PLB phosphorylation were attenuated by the addition of amitriptyline in perfused hearts from H2R-TG. In isolated electrically stimulated human atria, the PIE of histamine that was applied in increasing concentrations from 1 nM to 10 μM was reduced by 10-μM amitriptyline. In summary, we present functional evidence that amitriptyline also acts as an antagonist of contractility at H2Rs in H2R-TG mouse hearts and in the human heart which might in part explain the side effects of amitriptyline.

Prenatal ultrasound diagnosis of pulmonary atresia in combination with left atrial isomerism

2017 ◽  
Author(s):  
M Medvedev, M.V. Kubrina, O.S. Zarubina et all
Keyword(s):  
Left Atrial ◽  
Reverse Flow ◽  
Ductus Arteriosus ◽  
Pulmonary Atresia ◽  
Prenatal Ultrasound ◽  
Ultrasound Diagnosis ◽  
Right Atrial ◽  
Second Trimester ◽  
Left And Right ◽  
Atrial Isomerism

Two cases of prenatal ultrasound diagnosis of left atrial isomerism in the second trimester of gestation is presented. These two cases were in combination with pulmonary atresia and right aortic arch. Left atrial isomerism was identify by the digit-like shape of the left and right atrial appendages. The pulmonary atresia was identified on the basis of reverse flow in small pulmonary artery. A right aortic was identified by “U”-shaped confluence of aorta and ductus arteriosus in view of three vessels and trachea. The trachea was located between the vessels. The pregnancies were terminated and prenatal diagnosis was conformed at autopsy

scholarly journals Development of an automated closed-loop β-blocker delivery system to stably reduce myocardial oxygen consumption without inducing circulatory collapse in a canine heart failure model: a proof of concept study

2021 ◽  
Author(s):  
Takuya Nishikawa ◽  
Kazunori Uemura ◽  
Yohsuke Hayama ◽  
Toru Kawada ◽  
Keita Saku ◽  
...  
Keyword(s):  
Heart Failure ◽  
Oxygen Consumption ◽  
Myocardial Oxygen Consumption ◽  
Atrial Pressure ◽  
Right Atrial ◽  
Canine Heart ◽  
Circulatory Collapse ◽  
Inotropic Effects ◽  
Administration System ◽  
Β Blocker

AbstractBeta-blockers are well known to reduce myocardial oxygen consumption (MVO2) and improve the prognosis of heart failure (HF) patients. However, its negative chronotropic and inotropic effects limit their use in the acute phase of HF due to the risk of circulatory collapse. In this study, as a first step for a safe β-blocker administration strategy, we aimed to develop and evaluate the feasibility of an automated β-blocker administration system. We developed a system to monitor arterial pressure (AP), left atrial pressure (PLA), right atrial pressure, and cardiac output. Using negative feedback of hemodynamics, the system controls AP and PLA by administering landiolol (an ultra-short-acting β-blocker), dextran, and furosemide. We applied the system for 60 min to 6 mongrel dogs with rapid pacing-induced HF. In all dogs, the system automatically adjusted the doses of the drugs. Mean AP and mean PLA were controlled within the acceptable ranges (AP within 5 mmHg below target; PLA within 2 mmHg above target) more than 95% of the time. Median absolute performance error was small for AP [median (interquartile range), 3.1% (2.2–3.8)] and PLA [3.6% (2.2–5.7)]. The system decreased MVO2 and PLA significantly. We demonstrated the feasibility of an automated β-blocker administration system in a canine model of acute HF. The system controlled AP and PLA to avoid circulatory collapse, and reduced MVO2 significantly. As the system can help the management of patients with HF, further validations in larger samples and development for clinical applications are warranted.

scholarly journals Inducibility, but not stability, of atrial fibrillation is increased by NOX2 overexpression in mice

2021 ◽  
Author(s):  
Alexandra S Mighiu ◽  
Alice Recalde ◽  
Klemen Ziberna ◽  
Ricardo Carnicer ◽  
Jakub Tomek ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Superoxide Production ◽  
Right Atrial ◽  
Burst Stimulation ◽  
Lv Mass ◽  
Surface Ecg ◽  
Tissue Homogenates ◽  
Genotype Difference ◽  
Left And Right

Abstract Aims Gp91-containing NADPH oxidases (NOX2) are a significant source of myocardial superoxide production. An increase in NOX2 activity accompanies atrial fibrillation (AF) induction and electrical remodelling in animal models and predicts incident AF in humans; however, a direct causal role for NOX2 in AF has not been demonstrated. Accordingly, we investigated whether myocardial NOX2 overexpression in mice (NOX2-Tg) is sufficient to generate a favourable substrate for AF and further assessed the effects of atorvastatin, an inhibitor of NOX2, on atrial superoxide production and AF susceptibility. Methods and results NOX2-Tg mice showed a 2- to 2.5-fold higher atrial protein content of NOX2 compared with wild-type (WT) controls, which was associated with a significant (twofold) increase in NADPH-stimulated superoxide production (2-hydroxyethidium by HPLC) in left and right atrial tissue homogenates (P = 0.004 and P = 0.019, respectively). AF susceptibility assessed in vivo by transoesophageal atrial burst stimulation was modestly increased in NOX2-Tg compared with WT (probability of AF induction: 88% vs. 69%, respectively; P = 0.037), in the absence of significant alterations in AF duration, surface ECG parameters, and LV mass or function. Mechanistic studies did not support a role for NOX2 in promoting electrical or structural remodelling, as high-resolution optical mapping of atrial tissues showed no differences in action potential duration and conduction velocity between genotypes. In addition, we did not observe any genotype difference in markers of fibrosis and inflammation, including atrial collagen content and Col1a1, Il-1β, Il-6, and Mcp-1 mRNA. Similarly, NOX2 overexpression did not have consistent effects on RyR2 Ca2+ leak nor did it affect PKA or CaMKII-mediated RyR2 phosphorylation. Finally, treatment with atorvastatin significantly inhibited atrial superoxide production in NOX2-Tg but had no effect on AF induction in either genotype. Conclusion Together, these data indicate that while atrial NOX2 overexpression may contribute to atrial arrhythmogenesis, NOX2-derived superoxide production does not affect the electrical and structural properties of the atrial myocardium.

Simultaneous left and right atrial pressure curves during Valsalva's experiment

1955 ◽  
Vol 50 (5) ◽  
pp. 742-748 ◽  
Author(s):  
Viking Olov Björk ◽  
Gunnar Malmström
Keyword(s):  
Atrial Pressure ◽  
Right Atrial ◽  
Right Atrial Pressure ◽  
Left And Right

Simple single-section method for measurement of left and right atrial volumes with electron-beam CT

1999 ◽  
Vol 6 (8) ◽  
pp. 481-486 ◽  
Author(s):  
Matthew J. Budoff ◽  
Songshou Mao ◽  
ShaoJung Wang ◽  
Hamid Bakhsheshi ◽  
Bruce H. Brundage
Keyword(s):  
Electron Beam ◽  
Right Atrial ◽  
Section Method ◽  
Single Section ◽  
Electron Beam Ct ◽  
Left And Right

scholarly journals Minimal role for H1 and H2 histamine receptors in cutaneous thermal hyperemia to local heating in humans

2006 ◽  
Vol 100 (2) ◽  
pp. 535-540 ◽  
Author(s):  
Brett J. Wong ◽  
Sarah J. Williams ◽  
Christopher T. Minson
Keyword(s):  
Blood Flow ◽  
Receptor Antagonist ◽  
Skin Blood Flow ◽  
Local Heating ◽  
Histamine Receptor ◽  
Receptor Activation ◽  
Control Site ◽  
Doppler Flowmetry ◽  
Histamine Receptor Antagonist ◽  
And Control

The precise mechanism(s) underlying the thermal hyperemic response to local heating of human skin are not fully understood. The purpose of this study was to investigate a potential role for H1 and H2 histamine-receptor activation in this response. Two groups of six subjects participated in two separate protocols and were instrumented with three microdialysis fibers on the ventral forearm. In both protocols, sites were randomly assigned to receive one of three treatments. In protocol 1, sites received 1) 500 μM pyrilamine maleate (H1-receptor antagonist), 2) 10 mM l-NAME to inhibit nitric oxide synthase, and 3) 500 μM pyrilamine with 10 mM NG-nitro-l-arginine methyl ester (l-NAME). In protocol 2, sites received 1) 2 mM cimetidine (H2 antagonist), 2) 10 mM l-NAME, and 3) 2 mM cimetidine with 10 mM l-NAME. A fourth site served as a control site (no microdialysis fiber). Skin sites were locally heated from a baseline of 33 to 42°C at a rate of 0.5°C/5 s, and skin blood flow was monitored using laser-Doppler flowmetry (LDF). Cutaneous vascular conductance was calculated as LDF/mean arterial pressure. To normalize skin blood flow to maximal vasodilation, microdialysis sites were perfused with 28 mM sodium nitroprusside, and control sites were heated to 43°C. In both H1 and H2 antagonist studies, no differences in initial peak or secondary plateau phase were observed between control and histamine-receptor antagonist only sites or between l-NAME and l-NAME with histamine receptor antagonist. There were no differences in nadir response between l-NAME and l-NAME with histamine-receptor antagonist. However, the nadir response in H1 antagonist sites was significantly reduced compared with control sites, but there was no effect of H2 antagonist on the nadir response. These data suggest only a modest role for H1-receptor activation in the cutaneous response to local heating as evidenced by a diminished nadir response and no role for H2-receptor activation.

scholarly journals Heterotaxy syndrome: This is the left, right?

2015 ◽  
Vol 19 (2) ◽  
Author(s):  
Lili Huang ◽  
Belinda J. Mitchell ◽  
Savvas Andronikou ◽  
Zarina I. Lockhat ◽  
Farhana Suleman
Keyword(s):  
Morphological Characteristics ◽  
Imaging Modalities ◽  
Right Atrial ◽  
Abdominal Organ ◽  
Heterotaxy Syndrome ◽  
Diagnostic Challenge ◽  
Complex Disorder ◽  
Left And Right ◽  
Atrial Isomerism ◽  
Heterotaxy Syndromes

Heterotaxy syndrome is a rare and complex disorder of the chest and abdominal organ arrangements, and presents a diagnostic challenge to the radiologist. This article describes the morphological characteristics of heterotaxy and situs abnormalities, in particular left and right atrial isomerism, and suggests an approach in evaluating the spectrum of abnormalities associated with heterotaxy syndromes, using appropriate imaging modalities.

scholarly journals Disabling Gβγ SNARE interaction in transgenic mice disrupts GPCR-mediated presynaptic inhibition leading to physiological and behavioral phenotypes

2018 ◽  
Author(s):  
Zack Zurawski ◽  
Analisa D. Thompson Gray ◽  
Lillian J. Brady ◽  
Brian Page ◽  
Emily Church ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Calcium Channels ◽  
G Protein ◽  
Presynaptic Inhibition ◽  
Receptor Activation ◽  
G Protein Coupled Receptors ◽  
Voltage Gated ◽  
Voltage Gated Calcium Channels ◽  
Crucial Component ◽  
G Protein Coupled

ABSTRACTGi/o-coupled G-protein coupled receptors modulate neurotransmission presynaptically through inhibition of exocytosis. Release of Gβγ subunits decreases the activity of voltage-gated calcium channels (VGCC), decreasing excitability. A less understood Gβγ–mediated mechanism downstream of calcium entry is the binding of Gβγ to SNARE complexes. Here, we create a mouse partially deficient in this interaction. SNAP25Δ3 homozygote animals are developmentally normalbut impaired gait and supraspinal nociception. They also have elevated stress-induced hyperthermia and impaired inhibitory postsynaptic responses to α2A-AR, but normal inhibitory postsynaptic responses to Gi/o-coupled GABAB receptor activation. SNAP25Δ3 homozygotes have deficits in inhibition of hippocampal postsynaptic responses to 5 HT1b agonists that affect hippocampal learning. These data suggest that Gi/o-coupled GPCR inhibition of exocytosis through the Gβγ-SNARE interaction is a crucial component of numerous physiological and behavioral processes.

scholarly journals Impact of diabetes mellitus on the contractile properties of the left and right atrial myofilaments†

2018 ◽  
Vol 54 (5) ◽  
pp. 826-831 ◽  
Author(s):  
Constanze Bening ◽  
Khaled Alhussini ◽  
Elena-Aura Mazalu ◽  
Jonathan Yaqub ◽  
Khaled Hamouda ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Contractile Properties ◽  
Right Atrial ◽  
Left And Right
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