Related Experiment Video
Updated: Aug 5, 2026

Murine Isolated Heart Model of Myocardial Stunning Associated with Cardioplegic Arrest
Published on: August 6, 2015
Norepinephrine-induced delayed cardioprotection against stunning is at the expense of a higher postischemic
Ralph Marktanner1, Peter Nacke, Peter Feindt
1Department of Thoracic and Cardiovascular Surgery, Heinrich-Heine-University Düsseldorf, Germany. marktann@uni-duesseldorf.de
Objective:
alpha(1)-adrenoceptor activation confers myocardial protection from ischemic injury. We tested whether norepinephrine mediates delayed cardioprotection against stunning and whether this alters postischemic arrhythmias.
Methods:
New Zealand White rabbits were assigned to three groups: Control-group (n=7): no drugs. Norepinephrine-group (n=7): 75 microg norepinephrine/kg bodyweight (bw). Norepinephrine/prazosin-group (n=7):75 microg norepinephrine and 15 microg prazosin/kg bw. After 24 h, hearts were excised, perfused with buffer and subjected to 20 min of ischemia followed by 120 min of reperfusion.
Results:
(a) Developed pressures (dP) (P(syst)-P(diast)) at the end of reperfusion: C: 51.2+/-5.0%, NE: 71.7+/-5.1% (p<0.05 vs. C), NEP: 50.7+/-5.0%. (b) Ventricular extra beats (vebs) were detected throughout the experiments. C: 0.41+/-0.15 vebs/min, NE: 1.06+/-0.18 vebs/min (p<0.05 vs. C), NEP: 1.17+/-0.3 vebs/min.
Conclusion:
Norepinephrine confers delayed preconditioning against myocardial stunning via an alpha(1)-adrenoceptor mediated pathway. Norepinephrine-mediated preconditioning involves a beneficial effect towards stunning, but at the expense of a higher rate of postischemic ventricular arrhythmia.
Related Concept Videos
Desensitization and Tachyphylaxis
Several...
Antiarrhythmic Drugs: Class II Agents as β-Adrenergic Blockers
Heart Failure Drugs: Inotropic Agents
Heart Failure Drugs: β-Blockers
Cardiac Action Potential
The cardiac action potential process involves a series of phases characterized by the movement of ions across the cardiac cell membranes, leading to the depolarization and repolarization of the cardiac myocytes.
Ionic Basis of Cardiac Action Potentials
Cardiopulmonary Resuscitation IV: Pharmacological Management

