scholarly journals Exogenous connexin43-expressing autologous skeletal myoblasts ameliorate mechanical function and electrical activity of the rabbit heart after experimental infarction

2014 ◽  
Vol 96 (1) ◽  
pp. 42-53 ◽  
Author(s):  
Ieva Antanavičiūtė ◽  
Eglė Ereminienė ◽  
Vaidas Vysockas ◽  
Mindaugas Račkauskas ◽  
Vilius Skipskis ◽  
...  
Keyword(s):  
Electrical Activity ◽  
Rabbit Heart ◽  
Mechanical Function ◽  
Skeletal Myoblasts

scholarly journals Antiarrhythmic Properties of Elsholtzia ciliata Essential Oil on Electrical Activity of the Isolated Rabbit Heart and Preferential Inhibition of Sodium Conductance

Biomolecules ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 948
Author(s):  
Regina Mačianskienė ◽  
Lauryna Pudžiuvelytė ◽  
Jurga Bernatonienė ◽  
Mantė Almanaitytė ◽  
Antanas Navalinskas ◽  
...  
Keyword(s):  
Essential Oil ◽  
Electrical Activity ◽  
Rabbit Heart ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Cardiac Electrical Activity ◽  
Surface Ecg ◽  
Elsholtzia Ciliata ◽  
Qrs Duration ◽  
Mapping Techniques

Elsholtzia ciliata essential oil (E. ciliata) has been developed in Lithuania and internationally patented as exerting antiarrhythmic properties. Here we demonstrate the pharmacological effects of this herbal preparation on cardiac electrical activity. We used cardiac surface ECG and a combination of microelectrode and optical mapping techniques to track the action potentials (APs) in the Langendorff-perfused rabbit heart model during atrial/endo-/epi-cardial pacing. Activation time, conduction velocity and AP duration (APD) maps were constructed. E. ciliata increased the QRS duration and shortened QT interval of ECG at concentrations of 0.01–0.1 μL/mL, whereas 0.3 μL/mL (0.03%) concentration resulted in marked strengthening of changes. In addition, the E. ciliata in a concentration dependent manner reduced the AP upstroke dV/dtmax and AP amplitude as well as APD. A marked attenuation of the AP dV/dtmax and a slowing spread of electrical signals suggest the impaired functioning of Na+-channels, and the effect was use-dependent. Importantly, all these changes were at least partially reversible. Our results indicate that E. ciliata modulates cardiac electrical activity preferentially inhibiting Na+ conductance, which may contribute to its effects as a natural antiarrhythmic medicine.

Contribution of adenosine to isoproterenol-stimulated prostacyclin production in rabbit heart

1992 ◽  
Vol 263 (1) ◽  
pp. H218-H225
Author(s):  
C. Cano ◽  
Z. Qureshi ◽  
S. Carter ◽  
K. U. Malik
Keyword(s):  
Receptor Antagonist ◽  
Receptor Agonist ◽  
Rabbit Heart ◽  
Mechanical Function ◽  
Cgs 21680 ◽  
A1 Receptor ◽  
Prostacyclin Production ◽  
Prostacyclin Synthesis ◽  
A2 Receptors ◽  
Krebs Henseleit Buffer

This study investigated adenosine's contribution to isoproterenol-stimulated prostacyclin production, measured as 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) output, and mechanical function in the isolated rabbit heart perfused with Krebs-Henseleit buffer. The isoproterenol-induced increase in 6-keto-PGF1 alpha was diminished by adenosine (10 microM), the A1 receptor antagonist 1,3-dipropyl, 8-cyclopentylxanthine (DPCPX 0.06 microM), and the A2 receptor agonist CGS-21680 (0.6 microM); CGS-21680 did not decrease heart rate (HR) or myocardial contractility (dP/dt(max)). The isoproterenol-induced increase in 6-keto-PGF1 alpha was potentiated by the A1 receptor agonist 1-deaza,2-chloro,N6-cyclopentyladenosine (DCCA, 0.6 microM) and the A2 receptor antagonist 3,7-dimethyl,1-propargylxanthine (DMPX, 6 microM). The isoproterenol-induced increase in dP/dt(max) and HR was diminished by adenosine, DCCA, and DMPX. DPCPX enhanced dP/dt(max) and HR and prevented the decrease by adenosine and DCCA of the isoproterenol-induced increase in HR and dP/dt(max); the increase by DCCA but not the decrease by adenosine in 6-keto-PGF1 alpha output was abolished. DMPX abolished the effect of adenosine and CGS-21680 to reduce isoproterenol-stimulated 6-keto-PGF1 alpha. These data suggest that adenosine generated in response to isoproterenol attenuates its effect on HR and dP/dt(max) through A1 receptors and on prostacyclin synthesis via A2 receptors.

Low sodium attenuation of the Ca2+ paradox in the newborn rabbit myocardium

1985 ◽  
Vol 248 (3) ◽  
pp. H345-H349
Author(s):  
S. Uemura ◽  
H. Young ◽  
S. Matsuoka ◽  
J. M. Jarmakani
Keyword(s):  
Rabbit Heart ◽  
High Energy ◽  
Adult Rabbit ◽  
High Energy Phosphates ◽  
Mechanical Function ◽  
High Energy Phosphate ◽  
Newborn Rabbit ◽  
Low Sodium ◽  
Resting Tension ◽  
Rabbit Myocardium

The effect of low sodium (Na 24 mM) perfusate during Ca2+ depletion on mechanical function, tissue high-energy phosphate, creatine kinase (CK) release, and tissue potassium was studied in the arterially perfused newborn and adult rabbit heart. During Ca2+ depletion, the time for DT and +dT/dtmax to decline to half-maximal value in newborn muscles perfused with low Na (46 +/- 3 S) was significantly (P less than 0.05) longer than the value obtained with normal Na (14 +/- 1 S). Similar values were obtained in the adult. During Ca2+ repletion, the increase in resting tension and CK release was attenuated in the low Na groups, and the values in the newborn were significantly less than in the adult. The recovery of +dT/dtmax and tissue high-energy phosphates in the low Na groups were significantly greater than in the normal Na groups, and the values in the newborn were significantly greater than in the adult. These data suggest that low Na during the Ca2+-free period delays both cellular Ca2+ depletion during the Ca2+-free period and Ca2+ influx during Ca2+ repletion. This effect in the newborn is greater than in the adult and might be explained by Na+-Ca2+ exchange.

Heart rate reduction with ivabradine improves energy metabolism and mechanical function of isolated ischaemic rabbit heart

2009 ◽  
Vol 84 (1) ◽  
pp. 72-82 ◽  
Author(s):  
Claudio Ceconi ◽  
Anna Cargnoni ◽  
Gloria Francolini ◽  
Giovanni Parinello ◽  
Roberto Ferrari
Keyword(s):  
Heart Rate ◽  
Energy Metabolism ◽  
Rabbit Heart ◽  
Mechanical Function ◽  
Heart Rate Reduction ◽  
Rate Reduction

Ouabain effect on myocardial mechanical function and sodium pump in the fetus

1984 ◽  
Vol 246 (2) ◽  
pp. H213-H221
Author(s):  
T. Nakanishi ◽  
T. Shimizu ◽  
S. Uemura ◽  
J. M. Jarmakani
Keyword(s):  
Sodium Pump ◽  
Rabbit Heart ◽  
Age Group ◽  
Mechanical Function ◽  
Perfused Heart ◽  
Resting Tension ◽  
Age Related ◽  
Pump Activity ◽  
Heart Preparation ◽  
Fetal Muscle

Effects of ouabain (0.75, 1, 1.5, 2.5 or 5 X 10(-6) M) on the mechanical function and sodium pump were studied in the isolated arterially perfused fetal and newborn rabbit heart. Measurement of myocardial 86Rb+ active uptake was used as a marker of the sodium pump activity. The inotropic effect of ouabain in the fetus was not significantly different from that in the newborn; 2.5 X 10(-6) M ouabain caused mechanical toxicity (decrease in +dT/dtmax and increase in resting tension) in the fetus but not in the newborn. After ouabain infusion, both the inhibition of Rb+ uptake and the significant decrease in tissue potassium content were similar in the fetus and the newborn. In the fetal muscle perfused with low calcium (0.5 mM) solution, mechanical toxicity of ouabain was significantly less than in the control (1.5 mM Ca2+) solutions. High extracellular calcium (30 mM) per se caused mechanical toxicity in the fetus but not in the newborn. These data indicate that, in the isolated arterially perfused heart preparation, mechanical toxicity in the fetus is observed at lower ouabain concentrations than in the newborn. This difference in mechanical toxicity may not be explained by the age-related difference in sodium pump activity. The greater calcium toxicity in the fetus may be the reason for the increased ouabain toxicity in this age group.

Heat production and oxygen consumption of the isolated rabbit heart: Their relation to mechanical function

1977 ◽  
Vol 72 (1) ◽  
pp. 19-33 ◽  
Author(s):  
M. Theisohn ◽  
M. Friedrich ◽  
P. Justus ◽  
K. Güttler ◽  
W. Klaus
Keyword(s):  
Oxygen Consumption ◽  
Heat Production ◽  
Rabbit Heart ◽  
Mechanical Function ◽  
Isolated Rabbit Heart

Differences in myocardial ischemic tolerance between 1- and 7-day-old rabbits

1992 ◽  
Vol 70 (10) ◽  
pp. 1315-1323 ◽  
Author(s):  
Gary D. Lopaschuk ◽  
Marguerite A. Spafford
Keyword(s):  
Fatty Acids ◽  
Glucose Oxidation ◽  
Inferior Vena ◽  
Vena Cava ◽  
Rabbit Heart ◽  
Mechanical Function ◽  
Oxidation Rates ◽  
Increased Sensitivity ◽  
Lactate Levels ◽  
Product Accumulation

Between 1 and 7 days of life, the newborn rabbit heart shifts from predominantly using carbohydrates to predominantly using fatty acids as an energy substrate. We therefore used isolated working hearts from 1- or 7-day-old rabbits to determine the effects of fatty acids on myocardial glucose use and the ability of hearts to recover following various periods of transient no-flow ischemia. One-day-old hearts were perfused via the inferior vena cava and ejected buffer through the cannulated aorta and pulmonary artery. Seven-day-old hearts were perfused via the left atrium and ejected buffer through the cannulated aorta. To measure glucose use, hearts were perfused with 11 mM [3H,14C]glucose, 3% albumin, and 500 μU insulin/mL, in the presence or absence of 0.4 mM palmitate. In the absence of fatty acids, glycolytic rates were similar in 1- and 7-day-old hearts, whereas glucose oxidation rates were 5 times greater in 7-day-old hearts. Palmitate did not have any major effects on overall glucose use in 1-day-old hearts, but did markedly inhibit glycolysis and glucose oxidation in 7-day-old hearts. A series of hearts were also subjected to periods (25–60 min) of no-flow ischemia, followed by 30 min of aerobic reperfusion. In the absence of palmitate, 1-day-old hearts subjected to ischemic periods of up to 60 min recovered some degree of mechanical function during reperfusion, whereas 7-day-old rabbit hearts failed to recover if hearts were subjected to ischemic periods of 35 min or longer. Palmitate did not affect reperfusion recovery of 1-day-old rabbit hearts, but did improve recovery of 7-day-old hearts subjected to 40 min of ischemia. This effect in 7-day-old hearts was accompanied by a decrease in tissue lactate during ischemia. In 1-day-old hearts, a greater increase in lactate levels at the end of ischemia was seen, compared with 7-day-old hearts, and the increase was unaffected by the presence or absence of palmitate. These results demonstrate that the sensitivity of the rabbit heart to ischemia increases in the 1st week after birth. This increased sensitivity may be related to a combination of a decrease in glycolytic rates and an increase in sensitivity of hearts to glycolytic product accumulation during ischemia.Key words: newborn, ischemia, heart, fatty acids, glucose.

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