Journal of the American College of Cardiology
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J. Am. Coll. Cardiol. · Mar 1994
Randomized Controlled Trial Comparative Study Clinical TrialReexamination of the role of endogenous opiates in silent myocardial ischemia.
This study was designed to examine the role of beta-endorphin and met-enkephalin in the pathophysiology of silent myocardial ischemia, with emphasis on their role in the physiologic response to stress. ⋯ Beta-endorphin and met-enkephalin were similar in patients with painful and silent ischemia, and naloxone infusion did not influence anginal symptoms despite effective opiate receptor blockade and a reduction in somatic pain tolerance. These findings suggest that endogenous opiates do not play an important role in modulating symptoms in myocardial ischemia. The increase in beta-endorphin with exercise that coincided with an increase in plasma cortisol is most likely due to its release from the anterior pituitary gland as part of the physiologic stress response.