Negative Cardiac Inotropic Effects of Calcium Ion and of N-2-Hydroxyethylpiperazine-N′-2-ethanesulfonic Acid (HEPES) Buffer at Normal and Low Sodium Concentration

1974 ◽  
Vol 52 (5) ◽  
pp. 1025-1029 ◽  
Author(s):  
Peter E. Dresel
Keyword(s):  
Calcium Ions ◽  
Calcium Ion ◽  
Negative Inotropic Effect ◽  
Sodium Concentration ◽  
Contractile Force ◽  
Inotropic Effects ◽  
Hepes Buffer ◽  
Low Sodium ◽  
Ethanesulfonic Acid ◽  
Krebs Buffer

Isolated electrically driven left atria from rabbits were suspended in N-2-hydroxyethylpiperazine-N′-2-ethanesulfonic acid (HEPES) buffer and exposed to increasing concentration of calcium ions in the presence of different concentrations of sodium. Maximal contractile force occurred at 10 mM Ca and 145 mM Na. Higher concentrations of Ca had a negative inotropic effect. Lowering the Na concentration decreases the concentration of Ca required to observe the negative inotropy, until at 60–70 mM Na, it occurred at 5 mM Ca. This last result was confirmed in Krebs–Henseleit solution. Contractility at low Na and/or Ca media was less in HEPES than in Krebs buffer.

scholarly journals Sodium Radiofrequency Coils for Magnetic Resonance: From Design to Applications

Electronics ◽  
2021 ◽  
Vol 10 (15) ◽  
pp. 1788
Author(s):  
Giulio Giovannetti ◽  
Alessandra Flori ◽  
Nicola Martini ◽  
Roberto Francischello ◽  
Giovanni Donato Aquaro ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Sodium Concentration ◽  
Resonance Spectroscopy ◽  
Sodium Mri ◽  
Human Organs ◽  
Low Sodium ◽  
Radiofrequency Coils ◽  
Anatomical Imaging ◽  
Strong Gradient

Sodium (23Na) is the most abundant cation present in the human body and is involved in a large number of vital body functions. In the last few years, the interest in Sodium Magnetic Resonance Imaging (23Na MRI) has considerably increased for its relevance in physiological and physiopathological aspects. Indeed, sodium MRI offers the possibility to extend the anatomical imaging information by providing additional and complementary information on physiology and cellular metabolism with the heteronuclear Magnetic Resonance Spectroscopy (MRS). Constraints are the rapidly decaying of sodium signal, the sensitivity lack due to the low sodium concentration versus 1H-MRI induce scan times not clinically acceptable and it also constitutes a challenge for sodium MRI. With the available magnetic fields for clinical MRI scanners (1.5 T, 3 T, 7 T), and the hardware capabilities such as strong gradient strengths with high slew rates and new dedicated radiofrequency (RF) sodium coils, it is possible to reach reasonable measurement times (~10–15 min) with a resolution of a few millimeters, where it has already been applied in vivo in many human organs such as the brain, cartilage, kidneys, heart, as well as in muscle and the breast. In this work, we review the different geometries and setup of sodium coils described in the available literature for different in vivo applications in human organs with clinical MR scanners, by providing details of the design, modeling and construction of the coils.

Contractile effects of cardiac neuropeptides in isolated canine atrial and ventricular muscles

1989 ◽  
Vol 257 (4) ◽  
pp. H1082-H1087 ◽  
Author(s):  
D. F. Rigel ◽  
I. L. Grupp ◽  
A. Balasubramaniam ◽  
G. Grupp
Keyword(s):  
Isometric Force ◽  
Contractile Force ◽  
Adrenergic Blockade ◽  
Canine Heart ◽  
Inotropic Action ◽  
Inotropic Effects ◽  
Calcitonin Gene ◽  
Positive Inotropic Effects ◽  
The Right ◽  
Ventricular Trabeculae

Contractile effects of the cardiac neuropeptides vasoactive intestinal polypeptide (VIP), peptide histidine isoleucine (PHI), neuropeptide Y (NPY), calcitonin gene-related peptide (CGRP), and neurotensin (NT) were compared with those of l-isoproterenol (ISO) in isolated canine atrial and ventricular trabeculae muscles stimulated to contract at 1 Hz. In ventricular muscles, ISO, VIP, and PHI augmented developed isometric force by approximately 100%. VIP and PHI were three times and 1/10, respectively, as potent as ISO. VIP also exhibited positive inotropic effects in atrial trabeculae. The contractile responses to VIP were unchanged after beta-adrenergic blockade with nadolol at a concentration (10 microM) that shifted the ISO dose-response curve two to three orders of magnitude to the right. In atrial and ventricular trabeculae, NPY (1 microM) attenuated contractile force by 36 +/- 8 and 30 +/- 4%, respectively. Each peptide also caused comparable increases or decreases in the rate of development of force and the rate of relaxation. CGRP and NT caused no significant changes in developed force in either atrial or ventricular muscles in concentrations up to 1 microM. Our results indicate a potential positive inotropic action of endogenous VIP and PHI and a cardiodepressant effect of endogenous NPY in the canine heart.

scholarly journals Effects of clenbuterol on contractility and Ca2+ homeostasis of isolated rat ventricular myocytes

2008 ◽  
Vol 295 (5) ◽  
pp. H1917-H1926 ◽  
Author(s):  
U. Siedlecka ◽  
M. Arora ◽  
T. Kolettis ◽  
G. K. R. Soppa ◽  
J. Lee ◽  
...  
Keyword(s):  
Ventricular Myocytes ◽  
Severe Heart Failure ◽  
Negative Inotropic Effect ◽  
Chronic Administration ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Inotropic Response ◽  
Left Ventricular Assist Devices ◽  
Acute Effects ◽  
Inotropic Effects

Clenbuterol, a compound classified as a β2-adrenoceptor (AR) agonist, has been employed in combination with left ventricular assist devices (LVADs) to treat patients with severe heart failure. Previous studies have shown that chronic administration of clenbuterol affects cardiac excitation-contraction coupling. However, the acute effects of clenbuterol and the signaling pathway involved remain undefined. We investigated the acute effects of clenbuterol on isolated ventricular myocyte sarcomere shortening, Ca2+ transients, and L-type Ca2+ current and compared these effects to two other clinically used β2-AR agonists: fenoterol and salbutamol. Clenbuterol (30 μM) produced a negative inotropic response, whereas fenoterol showed a positive inotropic response. Salbutamol had no significant effects. Clenbuterol reduced Ca2+ transient amplitude and L-type Ca2+ current. Selective β1-AR blockade did not affect the action of clenbuterol on sarcomere shortening but significantly reduced contractility in the presence of fenoterol and salbutamol ( P < 0.05). Incubation with 2 μg/ml pertussis toxin significantly reduced the negative inotropic effects of 30 μM clenbuterol. In addition, overexpression of inhibitory G protein (Gi) by adenoviral transfection induced a stronger clenbuterol-mediated negative inotropic effect, suggesting the involvement of the Gi protein. We conclude that clenbuterol does not increase and, at high concentrations, significantly depresses contractility of isolated ventricular myocytes, an effect not seen with fenoterol or salbutamol. In its negative inotropism, clenbuterol predominantly acts through Gi, and the consequent downstream signaling pathways activation may explain the beneficial effects observed during chronic administration of clenbuterol in patients treated with LVADs.

scholarly journals THE EFFECT OF LACTIC ACID AND ARTIFICIAL SALIVA SOLUTION IMMERSION TO THE RELEASE OF CALCIUM IONS ON BIOACTIVE RESIN

2021 ◽  
Vol 6 (2) ◽  
pp. 190
Author(s):  
Dewi Puspitasari ◽  
Nurah Tajjalia ◽  
Diana Wibowo ◽  
Agung Satria Wardhana
Keyword(s):  
Lactic Acid ◽  
Acid Solution ◽  
Calcium Ions ◽  
Calcium Ion ◽  
Artificial Saliva ◽  
Distilled Water ◽  
Acid Condition ◽  
Ion Release ◽  
Lactic Acid Solution ◽  
Solution Increase

Background: Bioactive resin can release calcium ions when contact with solution media, even in acid condition. In the oral cavity, pH may change into acid condition due to the metabolic results of Streptococcus mutans. The bacteria metabolize carbohydrates into organic acids, one of which is lactic acid. Purpose: Analyze the effect of lactic acid solution and artificial saliva on the number of the release of calcium ions of bioactive resin. Methods: Forty-two specimens (diameter 15 mm x thickness 1 mm; n= 7/group fabricated with Activa™ Bioactive Restorative (Pulpdent). The specimens that meet the criteria were divided into 6 groups. The specimen was immersed for 1 and 7 days in the incubator at 37oC. The number of calcium ion release is measured using titration method. Results: Two Way Anova test and Post Hoc Bonferonni test showed there were significant differences among all group for lactic acid 1 day (4.040 ± 0.360) µg, artificial saliva 1 day (0.640 ± 0.338) µg, distilled water 1 day (1.040 ± 0.504) µg, lactic acid 7 days (5.400 ± 0.312), artificial saliva 7 days (1.640 ± 0.215) µg, distilled water 7 days (3.520± 0.356 µg). Conclusion: There was an influence of lactic acid and artificial saliva on the number of calcium ion releases of bioactive resin. Immersion of bioactive resin in the lactic acid solution increase the calcium ion releases and artificial saliva decrease the calcium ion release compared to distilled water. Keywords: artificial saliva, bioactive resin, calcium ion release, lactic acid

A fluoride selective water-soluble anion receptor based on a 1,2-phenylenediacetic acid and calcium ion dimer

2019 ◽  
Vol 43 (34) ◽  
pp. 13690-13695
Author(s):  
Dae Hyup Sohn ◽  
Nayeon Kim ◽  
Soonmin Jang ◽  
Jongmin Kang
Keyword(s):  
Calcium Ions ◽  
Calcium Ion ◽  
Water Soluble ◽  
Anion Receptor ◽  
Fluoride Ions

The dimeric receptor 1 from 1,2-phenylenediacetic acid and calcium ions recognized fluoride ions almost exclusively in 100% water.

Positive inotropic effects of low concentrations of leukotrienes C4 and D4 in rat heart

1990 ◽  
Vol 259 (4) ◽  
pp. H1239-H1246 ◽  
Author(s):  
M. Karmazyn ◽  
M. P. Moffat
Keyword(s):  
Calcium Channel ◽  
Positive Inotropic Effect ◽  
Negative Inotropic Effect ◽  
Bay K 8644 ◽  
Inotropic Effect ◽  
Receptor Interaction ◽  
Inotropic Effects ◽  
Coronary Pressure ◽  
Low Concentrations ◽  
Rat Hearts

We examined the effects of leukotrienes (LT) B4, C4, D4, and E4 (0.010-2.5 ng/ml) on contractile and coronary function in isolated rat hearts. Concentration-dependent effects were examined either by the cumulative addition of LTs or by addition of specific concentrations to individual preparations. Neither LTB4 nor LTE4 produced myocardial or coronary effects at any concentration, irrespective of addition protocol. At 0.010 ng/ml, both LTC4 and LTD4 produced an increase in force that was associated with a 30% elevation in coronary pressure. Further cumulative addition of either leukotriene resulted in a negative inotropic effect and a further increase in coronary pressure. In contrast, following single additions of LTC4 or LTD4 (0.01-0.50 ng/ml) a positive inotropic effect and an increased coronary pressure were observed. LTC4 or LTD4 at 0.5 ng/ml produced a negative inotropic effect in hearts pretreated with 0.01 ng/ml of LTD4 or LTC4, respectively. Reversal of this addition protocol resulted in a negative inotropic effect of either 0.01 ng/ml LTD4 or LTC4. Verapamil and nifedipine significantly attenuated the positive inotropic and coronary constricting effect of 0.5 ng/ml LTC4 and LTD4. The addition of either LT following BAY K 8644 resulted in a negative inotropic effect, in contrast to the positive inotropic influence seen with leukotriene alone. Our results demonstrate a positive inotropic effect of low concentrations of LTC4 and LTD4 concomitant with coronary artery constriction, a phenomenon determined by leukotriene addition protocols and suggestive of LTC4/LTD4 receptor interaction. The effects of calcium channel antagonists and BAY K 8644 on the inotropic response suggest a leukotriene-mediated activation of the calcium channel resulting in increased intracellular calcium concentrations.

Pyruvate potentiates inotropic effects of isoproterenol and Ca2+ in rabbit cardiac muscle preparations

2000 ◽  
Vol 279 (2) ◽  
pp. H702-H708 ◽  
Author(s):  
Hans-Peter Hermann ◽  
Oliver Zeitz ◽  
Boris Keweloh ◽  
Gerd Hasenfuss ◽  
Paul M. L. Janssen
Keyword(s):  
Energy Demand ◽  
Contractile Force ◽  
Potential Importance ◽  
Inotropic Response ◽  
Inotropic Effects ◽  
Individual Effects ◽  
Positive Inotropic Effects ◽  
Series Of Experiments ◽  
The Individual ◽  
Mere Addition

Catecholamines and elevated extracellular Ca2+concentration ([Ca2+]o) augment contractile force by increased Ca2+ influx and subsequent increased sarcoplasmic reticulum (SR) Ca2+ release. We tested the hypothesis that pyruvate potentiates Ca2+ release and inotropic response to isoproterenol and elevated [Ca2+]o, since this might be of potential importance in a clinical setting to circumvent deleterious effects on energy demand during application of catecholamines. Therefore, we investigated isometrically contracting myocardial preparations from rabbit hearts at 37°C, pH 7.4, and a stimulation frequency of 1 Hz. At a [Ca2+]o of 1.25 mM, pyruvate (10 mM) alone increased developed force (Fdev) from 1.89 ± 0.42 to 3.62 ± 0.62 (SE) mN/mm2 ( n = 8, P < 0.05) and isoproterenol (10−6 M) alone increased Fdev from 2.06 ± 0.55 to 25.11 ± 2.1 mN/mm2 ( P < 0.05), whereas the combination of isoproterenol and pyruvate increased Fdevoverproportionally from 1.89 ± 0.42 to 33.31 ± 3.18 mN/mm2 ( P < 0.05). In a separate series of experiments, we assessed SR Ca2+ content by means of rapid cooling contractures and observed that, despite no further increase in Fdev by increasing [Ca2+]o from 8 to 16 mM, 10 mM pyruvate could still increase Fdev from 26.4 ± 6.8 to 29.7 ± 7.1 mN/mm2( P < 0.05, n = 9) as well as the Ca2+ load of the SR. The results show that the positive inotropic effects of pyruvate potentiate the inotropic effects of isoproterenol or Ca2+, because in the presence of pyruvate, Ca2+ and isoproterenol induced larger increases in inotropy than can be calculated by mere addition of the individual effects.

HIGH AFFINITY CALCIUM BINDING TO DOMAINES OF PROTEIN C THAT ARE HOMOLOGUS TO THE EPIDERMAL GROWTH FACTOR

1987 ◽  
Author(s):  
A KÖhlin ◽  
J Stenflo
Keyword(s):  
Calcium Ions ◽  
Calcium Ion ◽  
Calcium Binding ◽  
Plasma Proteins ◽  
Metal Ion ◽  
Protein C ◽  
Protein S ◽  
Protein Z ◽  
High Affinity ◽  
Epidermal Growth

In addition to γ-carboxyglutamic acid (Gla)-dependent calcium binding all of the vitamin K-dependent plasma proteins, except prothrombin, have one or two high affinity calcium binding sites that do not require the Gla residues. A common denominator among these proteins (factors IX, X, protein C, protein Z and protein S) is that they have domaines that are homologus to the epidermal growth factor (EGF) precursor. In factors VII,IX,X, protein C and in protein Z the aminoterminal of two EGF homology regions contain one residue of β-hydroxyaspartic acid (Hya) whereas in protein S the aminoterminal EGF homology region contains Hya and the three following contain one β-hydroxyasparagine residue each.In an attempt to elucidate the role of the EGF homology regions in the Gla independent calcium binding we have isolated a tryptic fragment (residue 44-138) from the light chain of human protein C. The fragment was isolated using a monoclonal antibody that recognizes a calcium ion stabilized epitope that is expressed both in intact protein C and in protein C lacking the Gla domaine.The antibody bound the isolated EGF homology region in the presence of calcium ions but not in EDTA containing buffer. A calcium ion titration showed half maximal binding at approximately 200 μM Ca2+. The metal ion induced conformational change in the isolated fragment was also studied with affinity purified rabbit antibodies against Gla domainless protein C. Antibodies that bound in the presence of calcium ions and that could be eluted with EDTA recognized the metal ion induced conformational change in the isolated EGF homology domain. Our results suggest that one or both of the EGF homology regions are involved in the Gla-independent high affinity calcium binding in the vitamin K-dependent plasma proteins.

scholarly journals Probing the Role of Divalent Metal Ions in a Bacterial Psychrophilic Metalloprotease: Binding Studies of an Enzyme in the Crystalline State by X-Ray Crystallography

2003 ◽  
Vol 185 (14) ◽  
pp. 4195-4203 ◽  
Author(s):  
Stephanie Ravaud ◽  
Patrice Gouet ◽  
Richard Haser ◽  
Nushin Aghajari
Keyword(s):  
Metal Ions ◽  
Calcium Ions ◽  
Calcium Ion ◽  
Crystalline State ◽  
Zinc Ion ◽  
Binding Studies ◽  
X Ray ◽  
X Ray Crystallography ◽  
Catalytic Zinc

ABSTRACT The psychrophilic alkaline metalloprotease (PAP) produced by a Pseudomonas bacterium isolated in Antarctica belongs to the clan of metzincins, for which a zinc ion is essential for catalytic activity. Binding studies in the crystalline state have been performed by X-ray crystallography in order to improve the understanding of the role of the zinc and calcium ions bound to this protease. Cocrystallization and soaking experiments with EDTA in a concentration range from 1 to 85 mM have resulted in five three-dimensional structures with a distinct number of metal ions occupying the ion-binding sites. Evolution of the structural changes observed in the vicinity of each cation-binding site has been studied as a function of the concentration of EDTA, as well as of time, in the presence of the chelator. Among others, we have found that the catalytic zinc ion was the first ion to be chelated, ahead of a weakly bound calcium ion (Ca 700) exclusive to the psychrophilic enzyme. Upon removal of the catalytic zinc ion, the side chains of the active-site residues His-173, His-179 and Tyr-209 shifted ∼4, 1.0, and 1.6 Å, respectively. Our studies confirm and also explain the sensitivity of PAP toward moderate EDTA concentrations and propose distinct roles for the calcium ions. A new crystal form of native PAP validates our previous predictions regarding the adaptation of this enzyme to cold environments as well as the proteolytic domain calcium ion being exclusive for PAP independent of crystallization conditions.

Sign in / Sign up

Export Citation Format

Share Document