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Updated: Aug 6, 2026
Induction and Assessment of Ischemia-reperfusion Injury in Langendorff-perfused Rat Hearts
Published on: July 27, 2015
Endogenous catecholamines are not necessary for ischaemic preconditioning in the isolated perfused rat heart
E O Weselcouch1, A J Baird, P G Sleph
1Department of Pharmacology, Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, NJ 08543-4000.
Insights
Endogenous catecholamines are not mediators of myocardial ischaemic preconditioning. Depleting these substances did not alter the protective effects of preconditioning in rat hearts.
Area of Science:
- Cardiology
- Physiology
- Biochemistry
Background:
- Ischaemic preconditioning protects the myocardium from damage during reduced blood flow.
- The precise mechanisms underlying this protective effect remain largely unknown.
- Endogenous catecholamines are potential mediators that warrant investigation.
Purpose of the Study:
- To investigate the role of endogenous myocardial catecholamines in mediating the protective effects of ischaemic preconditioning.
- To test the hypothesis that catecholamines are essential for preconditioning's cardioprotective actions.
Main Methods:
- Experiments were conducted on isolated rat hearts.
- Catecholamine depletion was achieved using reserpine or 6-hydroxydopamine.
- The ability of noradrenaline to mimic preconditioning was also assessed.
Main Results:
- Catecholamine depletion did not impair ischaemic preconditioning's beneficial effects on cardiac function or reduce lactate dehydrogenase (LDH) release.
- Preconditioning significantly improved post-ischaemic cardiac function and decreased LDH release.
- Noradrenaline administration did not mimic the protective effects of preconditioning.
Conclusions:
- Endogenous catecholamines are not necessary for ischaemic preconditioning in isolated rat hearts.
- These substances play a minimal role in the functional responses observed during ischaemia and reperfusion.
Objective:
The mechanism of the protective effect of ischaemic preconditioning in the myocardium is not yet known. The aim of this study was to test the hypothesis that endogenous myocardial catecholamines may be mediators of preconditioning.
Methods:
To test whether endogenous catecholamines are involved in preconditioning, experiments were performed in hearts from rats which had been catecholamine depleted with either reserpine or 6-hydroxydopamine. Experiments were also done to determine if noradrenaline can mimic preconditioning.
Results:
Catecholamine depletion with either reserpine or 6-hydroxydopamine had no effect on preischaemic coronary flow or cardiac function. Ischaemic preconditioning (four episodes of 5 min global ischaemia and 5 min reperfusion) resulted in a significant increase in postischaemic cardiac function and a 50% decrease in lactate dehydrogenase (LDH) release following 30 min ischaemia and 30 min reperfusion compared with non-preconditioned hearts. Reserpine pretreatment did not affect the response to ischaemia or to preconditioning, although LDH release tended to be greater than in normal hearts, especially in the non-preconditioned group. Although 6-hydroxydopamine significantly increased postischaemic cardiac function in the preconditioned group, no other index of ischaemic damage (for example, LDH release, left ventricular end diastolic pressure) was affected. Further studies showed that 10 nmol.min-1 noradrenaline did not affect the severity of ischaemia, indicating that it does not mimic preconditioning.
Conclusions:
Endogenous catecholamines are not necessary for ischaemic preconditioning in isolated rat hearts and play little or no role in the functional responses to ischaemia.
