Microwave-induced chronotropic effects in the isolated rat heart

1977 ◽  
Vol 5 (4) ◽  
pp. 395-409 ◽  
Author(s):  
R. G. Olsen ◽  
J. L. Lords ◽  
C. H. Durney
Keyword(s):  
Rat Heart ◽  
Isolated Rat Heart ◽  
Chronotropic Effects ◽  
Isolated Rat

scholarly journals The dose-dependent effect of chronic Verapamil treatment on cardiac function in isolated rat heart with Hypertension

EP Europace ◽  
2021 ◽  
Vol 23 (Supplement_3) ◽  
Author(s):  
S Simovic ◽  
J Jeremic ◽  
G Davidovic ◽  
I Srejovic ◽  
V Zivkovic ◽  
...  
Keyword(s):  
Heart Rate ◽  
Rat Heart ◽  
Coronary Flow ◽  
Chronic Treatment ◽  
Low Dose ◽  
Isolated Rat Heart ◽  
High Dose ◽  
Chronotropic Effects ◽  
Dose Dependent ◽  
Isolated Rat

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Verapamil, a calcium channel blocker, is used for treatment of hypertension, paroxysmal supraventricular tachycardia  and angina pectoris. It primarily blocks L-type calcium channels preventing excessive influx of calcium into cardiomyocytes, leading to negative inotropic effect, and smooth muscle cells resulting in reduced relaxation of vasculature. With calcium antagonism it also causes negative chronotropic effect. However, there is no data on it’s dose-dependent effects on cardiac dynamic parameters and heart rate on isolated rat heart with hypertension. Purpose To investigate chronic, dose-dependent effects of Verapamil on cardiodynamic parameters in isolated rat heart with hypertension. Methods The present 4-week study was carried out on 24 spontaneously hypertensive Wistar Kyoto male rats  (6 weeks old): Control (n = 6), rats treated with 0.5 mg/kg/day of Verapamil (n = 6), rats treated with 5 mg/kg/day of Verapamil (n = 6) and rats treated with 50 mg/kg/day of Verapamil (n = 6). Isolated rat hearts were perfused on Langendorff perfusion apparatus. Results Chronic, low-dose Verapamil treatment significantly depressed function of all cardiodynamic parameters of the hypertensive heart when compared to the rats treated with higher doses of Verapamil (p < 0.001), except on the coronary flow and heart rate when compared to the Control (p= 0.137; p = 1.000, respectively). There was no significant differences between Verapamil in middle dose (5 mg/kg/day) and the Control group in inotropic (p = 0.415) and lusitropic (p = 1.000) effects, while it significantly lowered values of coronary flow (p = 0.002). It achieved significantly lower inotropic, lusitropic and chronotropic effects (p < 0.001) than high Verapamil dose and significantly better inotropic (p = 0.017), lusitropic (p < 0.001), but not chronotropic effects than low-dose Verapamil treatment (p = 0.179). High-dose, chronic treatment with Verapamil significantly intensified function of  the isolated rat heart with hypertension when compared to Control and lower doses of Verapamil (p < 0.001), without significant effects on coronary flow (p = 0.363). Conclusions Chronic treatment with Verapamil in high dose achieved better inotropic, chronotropic and lusitropic effects than treatment in low and middle doses of Verapamil, without significant effects on coronary flow. There is dose-depended effect of chronic Verapamil treatment on cardiac function of isolated rat heart with hypertension.

The ino- and chronotropic effects of imidazoline drugs on isolated rat heart atria – are I1- imidazoline receptors involved?

2013 ◽  
Vol 65 ◽  
pp. 40-41
Author(s):  
Justyna Długokęcka ◽  
Magdalena Grudzień ◽  
Antoni Nasal ◽  
Aleksandra Radwańska ◽  
Roman Kaliszan
Keyword(s):  
Rat Heart ◽  
Isolated Rat Heart ◽  
Imidazoline Receptors ◽  
Chronotropic Effects ◽  
Heart Atria ◽  
Isolated Rat

Effect of Hydrogen Sulfide on Reactions of Isolated Rat Heart under Volume Load and Ischemia-Reperfusion

2013 ◽  
Vol 4 (3) ◽  
pp. 201-212
Author(s):  
Tetyana V Shimanskaya ◽  
Yulia V. Goshovska ◽  
Olena M. Semenykhina ◽  
Vadim F. Sagach
Keyword(s):  
Hydrogen Sulfide ◽  
Rat Heart ◽  
Ischemia Reperfusion ◽  
Isolated Rat Heart ◽  
Volume Load ◽  
Isolated Rat

‘Cross Talk’ Between Opioid Peptide and Adrenergic Receptor Signaling in Isolated Rat Heart

Circulation ◽  
1997 ◽  
Vol 95 (8) ◽  
pp. 2122-2129 ◽  
Author(s):  
Salvatore Pepe ◽  
Rui-Ping Xiao ◽  
Charlene Hohl ◽  
Ruth Altschuld ◽  
Edward G. Lakatta
Keyword(s):  
Cross Talk ◽  
Rat Heart ◽  
Adrenergic Receptor ◽  
Opioid Peptide ◽  
Isolated Rat Heart ◽  
Receptor Signaling ◽  
Isolated Rat

Comparison of Polarized and Depolarized Arrest in the Isolated Rat Heart for Long-term Preservation

Circulation ◽  
1997 ◽  
Vol 96 (9) ◽  
pp. 3148-3156 ◽  
Author(s):  
A. K. Snabaitis ◽  
M. J. Shattock ◽  
D. J. Chambers
Keyword(s):  
Rat Heart ◽  
Isolated Rat Heart ◽  
Long Term Preservation ◽  
Isolated Rat

scholarly journals Correction to: Peculiar Aspects in Influence of α1-Adrenoceptor Stimulation on Isolated Rat Heart

2021 ◽  
Author(s):  
T. L. Zefirov ◽  
I. I. Khabibrakhmanov ◽  
N. I. Ziyatdinova ◽  
A. L. Zefirov
Keyword(s):  
Rat Heart ◽  
Isolated Rat Heart ◽  
Isolated Rat

Dobutamine responsiveness, PET mismatch, and lack of necrosis in low-flow ischemia: is this hibernation in the isolated rat heart?

2003 ◽  
Vol 285 (1) ◽  
pp. H316-H324 ◽  
Author(s):  
Richard Southworth ◽  
Pamela B. Garlick
Keyword(s):  
Rat Heart ◽  
Recovery Of Function ◽  
Electron Microscopic Examination ◽  
Left Ventricular ◽  
Isolated Rat Heart ◽  
Low Flow ◽  
Hibernating Myocardium ◽  
Heart Model ◽  
Electron Microscopic ◽  
Isolated Rat

The clinical hallmarks of hibernating myocardium include hypocontractility while retaining an inotropic reserve (using dobutamine echocardiography), having normal or increased [18F]fluoro-2-deoxyglucose-6-phosphate (18FDG6P) accumulation associated with decreased coronary flow [flow-metabolism mismatch by positron emission tomography (PET)], and recovering completely postrevascularization. In this study, we investigated an isolated rat heart model of hibernation using experimental equivalents of these clinical techniques. Rat hearts ( n = 5 hearts/group) were perfused with Krebs-Henseleit buffer for 40 min at 100% flow and 3 h at 10% flow and reperfused at 100% flow for 30 min (paced at 300 beats/min throughout). Left ventricular developed pressure fell to 30 ± 8% during 10% flow and recovered to 90 ± 7% after reperfusion. In an additional group, this recovery of function was found to be preserved over 2 h of reperfusion. Electron microscopic examination of hearts fixed at the end of the hibernation period demonstrated a lack of ischemic injury and an accumulation of glycogen granules, a phenomenon observed clinically. In a further group, hearts were challenged with dobutamine during the low-flow period. Hearts demonstrated an inotropic reserve at the expense of increased lactate leakage, with no appreciable creatine kinase release. PET studies used the same basic protocol in both dual- and globally perfused hearts (with 250MBq18FDG in Krebs buffer ± 0.4 mmol/l oleate). PET data showed flow-metabolism “mismatch;” whether regional or global,18FDG6P accumulation in ischemic tissue was the same as (glucose only) or significantly higher than (glucose + oleate) control tissue (0.023 ± 0.002 vs. 0.011 ± 0.002 normalized counts · s-1· g-1· min-1, P < 0.05) despite receiving 10% of the flow. This isolated rat heart model of acute hibernation exhibits many of the same characteristics demonstrated clinically in hibernating myocardium.

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