title: Endorphins are related to pain perception in coronary artery disease.
abstract: Plasma beta-endorphin levels were measured by radioimmunoassay before and after exercise in 25 patients with coronary artery disease. Eighteen patients were men and 7 were women; age range was 36 to 75 years (mean 60). All patients had angina pectoris, a positive treadmill test response or positive exercise radionuclide findings. The mean preexercise plasma endorphin level was 4.9 +/- 3.0 pmol/liter (range 0.7 to 13.5). The mean postexercise plasma endorphin level of 6.6 +/- 4.6 mol/liter (range 0 to 19.5) was significantly higher (p less than 0.05). A significant positive correlation was seen between postexercise endorphin levels and time to onset of angina (r = 0.4, p = 0.03). There were negative correlations between postexercise endorphin levels and occurrence (r = -0.4, p = 0.04) and duration of angina (r = -0.4, p = 0.05). No association was found for maximal heart rate-blood pressure product, workload, time to ST-segment depression or stress ejection fraction. A positive correlation was found between rest left ventricular ejection fraction and postexercise endorphin levels (r = 0.5, p = 0.02). In conclusion, in patients with exercise-induced myocardial ischemia, plasma beta-endorphin levels are increased after exercise; postexercise endorphin levels are related to timing and occurrence (presence or absence) of angina; and endorphins may alter the perception of pain caused by myocardial ischemia.
mesh_terms: D000328:Adult; D000368:Aged; D000787:Angina Pectoris / Q000097:blood / Q000150:complications / Q000523:psychology; D003327:Coronary Disease / Q000097:blood / Q000503:physiopathology* / Q000523:psychology; D004723:Endorphins / Q000097:blood / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000097:blood* / Q000523:psychology; D005082:Physical Exertion; D012684:Sensory Thresholds
chemical_list: D004723:Endorphins