Effect of Trilinolein on Superoxide Dismutase Activity and Left Ventricular Pressure in Isolated Rat Hearts Subjected to Hypoxia and Normoxic Perfusion

Pharmacology ◽  
1997 ◽  
Vol 55 (5) ◽  
pp. 252-258 ◽  
Author(s):  
Paul Chan ◽  
Chiang-Shan Niu ◽  
Brian Tomlinson ◽  
Chi-Tzong Hong ◽  
Jane-Pyng Chen ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Superoxide Dismutase Activity ◽  
Ventricular Pressure ◽  
Rat Hearts ◽  
Isolated Rat

Cardiac Effects of Postconditioning Depend Critically on the Duration of Reperfusion and Reocclusion Episodes

2010 ◽  
Vol 13 (1) ◽  
pp. 52 ◽  
Author(s):  
Bruno Botelho Pinheiro ◽  
Alfredo In�cio Fiorelli ◽  
Otoni Moreira Gomes ◽  
Borut Gersak
Keyword(s):  
Systolic Pressure ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Ischemic Postconditioning ◽  
Ventricular Pressure ◽  
Maximum Speed ◽  
P Value ◽  
Rat Hearts ◽  
Stabilization Period ◽  
Isolated Rat

Objective: The objective of the present study was to evaluate the effects of ischemic postconditioning on left ventricular function in isolated rat hearts.Methods: The hearts of 24 Wistar rats were were isolated, perfused immediately, and distributed into 3 groups: GI, control (n = 8); GII, three 10-second cycles of postconditioning (n = 8); and GIII, three 30-second cycles of postconditioning (n = 8). After a 15-minute stabilization period, all hearts underwent 20 minutes of global ischemia following 20 minutes of reperfusion. At times t0 (control), t5, t10, t15, and t20 (0, 5, 10, 15, and 20 minutes of reperfusion, respectively), we recorded the heart rate, coronary flow, systolic pressure, +(dP/dt)max (maximum speed of increase in the left ventricular pressure), and -(dP/dt)max (maximum speed of decrease in the left ventricular pressure). Data were analyzed by a 1-way analysis of variance, followed by the Tukey test; a P value .05); however, statistically significant differences in +(dP/dt)max between GII and GI and between GII and GIII occurred at t20 (GI, 1409.0 415.1 mm Hg/s; GII, 1917.3 403.0 mm Hg/s; GIII, 1344.8 355.8 mm Hg/s) (GII versus GI, P = .04; GII versus GIII, P = .02).Conclusion: Ischemic postconditioning with three 10-second cycles of reperfusion/reocclusion was demonstrated effective for preserving +(dP/dt)max in isolated rat hearts that underwent 20 minutes of ischemia following 20 minutes of reperfusion.

Detection of Cardiac Variability in the Isolated Rat Heart

2006 ◽  
Vol 8 (1) ◽  
pp. 55-66 ◽  
Author(s):  
Autumn M. Schumacher ◽  
Joseph P. Zbilut ◽  
Charles L. Webber ◽  
Dorie W. Schwertz ◽  
Mariann R. Piano
Keyword(s):  
Rat Heart ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Isolated Rat Heart ◽  
Rat Hearts ◽  
Before And After ◽  
Quantification Analysis ◽  
Physical Attributes ◽  
Cardiac Variability ◽  
Isolated Rat

Cardiac variability can be assessed from two perspectives: beat-to-beat performance and continuous performance during the cardiac cycle. Linear analysis techniques assess cardiac variability by measuring the physical attributes of a signal, whereas nonlinear techniques evaluate signal dynamics. This study sought to determine if recurrence quantification analysis (RQA), a nonlinear technique, could detect pharmacologically induced autonomic changes in the continuous left ventricular pressure (LVP) and electrographic (EC) signals from an isolated rat heart—a model that theoretically contains no inherent variability. LVP and EC signal data were acquired simultaneously during Langendorff perfusion of isolated rat hearts before and after the addition of acetylcholine (n = 11), norepinephrine (n = 12), or no drug (n = 12). Two-minute segments of the continuous LVP and EC signal data were analyzed by RQA. Findings showed that%recurrence,%determinism, entropy, maxline, and trend from the continuous LVP signal significantly increased in the presence of both acetylcholine and norepinephrine, although systolic LVP significantly increased only with norepinephrine. In the continuous EC signal, the RQA trend variable significantly increased in the presence of norepinephrine. These results suggest that when either the sympathetic or parasympathetic division of the autonomic nervous system overwhelms the other, the dynamics underlying cardiac variability become stationary. This study also shows that information concerning inherent variability in the isolated rat heart can be gained via RQA of the continuous cardiac signal. Although speculative, RQA may be a tool for detecting alterations in cardiac variability and evaluating signal dynamics as a nonlinear indicator of cardiac pathology.

Positive staircase effect in the rat heart

1975 ◽  
Vol 228 (2) ◽  
pp. 360-364 ◽  
Author(s):  
PD Henry
Keyword(s):  
Left Ventricular Pressure ◽  
Peak Stress ◽  
Ventricular Myocardium ◽  
Left Ventricular ◽  
Papillary Muscles ◽  
Apparent Lack ◽  
Rat Hearts ◽  
Staircase Effect ◽  
Krebs Buffer ◽  
Isolated Rat

The apparent lack of a positive staircase effect in ray myocardium may reflect inadequate metabolic support. Isolated rat hearts (n equals 10) were perfused at 37 degrees C with Krebs buffer containing 5 mM glucose. In 10 preparations increases in heart rate from 240 to 480/min resulted in twofold increases in left ventricular pressure and dP/dt. Pacing at a rate of 480/min resulted in mechanical deterioration of the preparation and in 50% decreases of myocardial ATP concentration within a 10-min period. Hearts of open-chest rats driven at the same rate for the same period maintained normal ATP stores. In isolated papillary muscles contracting isometrically at a rate of 30/min, peak stress 15g/mm2 (mean plus or minus SE, n equals 8) and was not changed by increasing the concentration of glucose from 5 to 30 mM. When frequency was raised from 30 to 300/min, stress declined to 5.0 plus or minus .15 g/mm2 in the presence of 5mM glucose (P smaller than .001) but increased to 8.8 plus or minus .21 g/mm2 (P smaller than 0.001) in the presence of 30 mM glucose. Thus, rat ventricular myocardium exhibits a positive staircase effect at physiological heart rates when metabolic support is adequate.

scholarly journals The Effects of Potassium Cyanide on the Functional Recovery of Isolated Rat Hearts after Ischemia and Reperfusion: The Role of Oxidative Stress

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Anica M. Petkovic ◽  
Vladimir Lj. Jakovljevic ◽  
Jovana V. Bradic ◽  
Jovana N. Jeremic ◽  
Nevena S. Jeremic ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Functional Recovery ◽  
Heart Function ◽  
Potassium Cyanide ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Global Ischemia ◽  
Albino Rats ◽  
Rat Hearts ◽  
Isolated Rat

This investigation is aimed at examining the effects of pharmacological PostC with potassium cyanide (KCN) on functional recovery, gene expression, cytochrome c expression, and redox status of isolated rat hearts. Rats were divided into the control and KCN groups. The hearts of male Wistar albino rats were retrogradely perfused according to the Langendorff technique at a constant perfusion pressure of 70 cmH2O. After stabilisation, control hearts were subjected to global ischemia (5 minutes), followed by reperfusion (5 minutes), while experimental hearts underwent global ischemia (5 minutes) followed by 5 minutes of reperfusion with 10 μmol/L KCN. The following parameters of heart function were measured: maximum and minimum rates of pressure development, systolic and diastolic left ventricular pressure, heart rate, and coronary flow. Levels of superoxide anion radical, hydrogen peroxide, nitrites, and index of lipid peroxidation (measured as thiobarbituric acid-reactive substances) were measured in coronary venous effluent, and activity of catalase was determined in heart tissue. Expression of Bax, Bcl-2, SOD-1, SOD-2, and cytochrome c was studied as well. It was shown that expression of Bax, Bcl-2, and SOD-2 genes did not significantly differ between groups, while expression of SOD-1 gene and cytochrome c was lower in the KCN group. Our results demonstrated that KCN improved the recovery of myocardial contractility and systolic and diastolic function, enhanced catalase activity, and diminished generation of prooxidants. However, all possible mechanisms and potential adverse effects of KCN should be further examined in the future.

Voltage-sensitive dye RH421 increases contractility of cardiac muscle

1998 ◽  
Vol 76 (12) ◽  
pp. 1146-1150 ◽  
Author(s):  
Yuanna Cheng ◽  
David R Wagoner ◽  
Todor N Mazgalev ◽  
Patrick J Tchou ◽  
Igor R Efimov
Keyword(s):  
Imaging Techniques ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Motion Artifacts ◽  
Ventricular Pressure ◽  
Ventricular Contractility ◽  
Voltage Sensitive Dye ◽  
Cell Shortening ◽  
Rat Hearts ◽  
Butanedione Monoxime

Voltage-sensitive dyes and imaging techniques have proved to be indispensable tools for use in in vitro electrophysiological studies. To avoid motion artifacts in optical recordings, electromechanical uncouplers such as 2,3-butanedione monoxime (BDM) are required. In this study, we sought to determine whether the voltage-sensitive dye RH421 had an effect on the contractility of heart muscle, either alone or in the presence of BDM. Ventricular contractility was studied in (i) isolated rat myocytes and (ii) Langendorff-perfused rat hearts under control conditions, and during perfusion with RH421 or RH421 + BDM. The following results were obtained. (i) The amplitude of cell shortening increased progressively from 6.24 ± 0.64 to 9.95 ± 1.02 µm during 15 min of superfusion with 5 µM RH421 (n = 11), and further increased to 12.54 ± 0.97 µm during washout. In seven cells first perfused with 15 mM BDM and then with 15 mM BDM + 5 µM RH421, the amplitude of the cell shortening first decreased from 5.17 ± 0.51 to 0.41 ± 0.19 µm, then the amplitude increased to 2.63 ± 0.25 µm. (ii) Left ventricular pressure (LVP) of the heart (n = 7) was reduced by 15 mM BDM from 60.7 ± 2.5 to 2.8 ± 0.5 mmHg (1 mmHg = 133.3 Pa). LVP increased to 12.8 ± 1.1 mmHg during subsequent perfusion with 10 µM RH421 in the presence of BDM and did not change (LVP = 12.4 ± 2.4 mmHg) during washout of the dye. Therefore, RH421 increased the contractility of rat hearts and isolated myocytes with and without BDM.Key words: voltage-sensitive dye RH421, 2,3-butanedione monoxime, left ventricular pressure, cell shortening, contractility.

Endogenous adenosine inhibits catecholamine contractile responses in normoxic hearts

1986 ◽  
Vol 251 (2) ◽  
pp. H455-H462 ◽  
Author(s):  
J. G. Dobson ◽  
R. W. Ordway ◽  
R. A. Fenton
Keyword(s):  
Adenosine Deaminase ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Ventricular Pressure ◽  
Contractile Responses ◽  
Beta Adrenoceptor ◽  
Isolated Hearts ◽  
Endogenous Adenosine ◽  
Rat Hearts ◽  
Pressure Development

The importance of endogenous myocardial adenosine in attenuating catecholamine-elicited contractile responses was investigated in perfused oxygenated rat hearts. Perfusion of the isolated hearts with adenosine deaminase potentiated the isoproterenol-induced increases of three contractile variables (left ventricular pressure development and rates of both left ventricular pressure development and relaxation). The peak (maximal, within 30 s) and maintained (after 1 min) increases of the contractile variables caused by 10(-8) M isoproterenol were enhanced by 15-22 and 31-43%, respectively. Adenosine deaminase appeared in epicardial surface transudates of similarly perfused hearts, indicating that the enzyme had entered the myocardial interstitial space. Isoproterenol alone elevated the release of adenosine into coronary effluents of isoproterenol-stimulated hearts, and adenosine deaminase prevented the release of the nucleoside. The higher the level of adenosine in the effluent, the greater the reduction of the peak contractile variables. Phenylisopropyladenosine at 10(-8) M prevented the adenosine deaminase potentiation of 10(-9) M isoproterenol-induced contractile responses. The adenosine analogue at 10(-6) M blocked completely the isoproterenol-produced increases in the contractile variables. These results suggest that endogenous adenosine prevents full mechanical responsiveness to beta-adrenoceptor stimulation in the oxygenated myocardium. In addition, the findings support the notion that adenosine serves as an important negative feedback modulator in the oxygenated heart.

Mechanical workload-myocardial water content relationship in isolated rat hearts

1997 ◽  
Vol 273 (1) ◽  
pp. H271-H278
Author(s):  
E. R. Schertel ◽  
R. M. Daye ◽  
D. E. McClure ◽  
T. Lai ◽  
M. Miyamoto ◽  
...  
Keyword(s):  
Water Content ◽  
Isolated Heart ◽  
Left Ventricular Pressure ◽  
Myocardial Edema ◽  
Left Ventricular ◽  
Edema Formation ◽  
Perfused Rat Heart ◽  
Rat Hearts ◽  
Heart Preparation ◽  
Isolated Rat

We tested the hypothesis that the mechanical workload of the heart inversely determines the rate of myocardial edema formation in an isolated, perfused rat heart preparation. Heart rate (HR) was varied in three groups by pacing at 125 (HR125), 250 (HR250), or 350 beats/min (HR350). Left ventricular pressure (LVP) was varied in two additional groups by pacing at 250 beats/min and with the addition of either epinephrine (Epi) or propranolol (Pro) to the perfusate. In five otherwise identical groups, variation of coronary vascular resistance was minimized by adenosine. Myocardial water content (MWC) varied significantly and inversely with HR in the HR125, HR250, and HR350 groups. MWC of the HR250 group was significantly less than that of the Pro group but did not differ from the Epi group. However, when adenosine was used, MWC had significant inverse relationships with HR and LVP. We concluded that the mechanical workload of the heart inversely determines the rate and degree of myocardial edema formation in this isolated heart preparation, and both HR and LVP are determinants of this relationship.

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