Myocardial turnover of endogenous opioids and calcitonin-gene-related peptide in the human heart and the effects of spinal cord stimulation on pacing-induced angina pectoris.

Earlier studies have shown that spinal cord stimulation (SCS) has antianginal and anti-ischemic effects in severe coronary artery disease. In the present study, 14 patients were subjected to right-sided atrial catheterization and atrial pacing. The patients were paced to angina during a control session and during spinal cord stimulation. Myocardial extraction of beta-endorphin (BE) during control pacing (8 +/- 22%) changed to release at the maximum pacing rate during treatment (-21 +/- 47%, a negative value representing release). Furthermore, the results indicate local myocardial turnover of leuenkephalin, BE and calcitonin-gene-related peptide. In addition, it is implied that SCS may induce myocardial release of BE which could explain the beneficial effects in myocardial ischemia.