August 1, 1994Circulation
Alpha-adrenoceptor stimulation with exogenous norepinephrine or release of endogenous catecholamines mimics ischemic preconditioning.
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Discussion
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Implication
Randomized trial demonstrates reduced infarct size with norepinephrine and tyramine in rabbits, suggesting a protective cardiac effect.
Key Points
- The aim was to determine if transient alpha-adrenoceptor stimulation could mimic myocardial protection seen in ischemic preconditioning.
- Administered norepinephrine or saline for 5 minutes before coronary occlusion in rabbits (N=...).
- Measured infarct size and area of risk during 30-minute occlusion and 4-hour reperfusion.
- Examined effects of tyramine-induced catecholamine release and alpha-adrenergic blockade with prazosin.
- Norepinephrine reduced infarct size (AN/AR, 0.17 +/- 0.04 vs 0.31 +/- 0.04; P < .02).
- Tyramine pretreatment resulted in smaller infarct sizes (AN/AR, 0.16 +/- 0.04 vs 0.41 +/- 0.07; P < .01).
- Alpha-adrenergic blockade eliminated the protective effect of norepinephrine.
Cite This Study
Bankwala et al. (1994) studied this question.