Role of endogenous opioids on nociceptive threshold in patients with exercise-induced myocardial ischemia.
To evaluate whether endogenous opioids (EO) play a role in the perception of anginal pain, a randomized double blind clinical trial, using naloxone (N) and placebo (P) and measuring beta-endorphin (beta-ep) plasma levels, was performed. We studied 10 patients with angiographically assessed coronary artery disease (CAD) and stable exercise-induced myocardial ischemia (established by 2 preliminary bicycle ergometric tests) of whom 5 symptomatic (SYM) and 5 asymptomatic (ASYM) and 5 subjects without CAD as a control group (CON). On a third exercise test the beta-ep plasma level (fmol/ml) was measured at rest (SYM 5.4 +/- 2.3 vs ASYM 7.2 +/- 2.3 vs CON 6.8 +/- 2.6, NS), at peak exercise (SYM 4.4 +/- 1.8 vs ASYM 8.0 +/- 4.2 and vs CON 6.2 +/- 2.7, NS) and during recovery (SYM 7.5 +/- 4.2 vs ASYM 7.2 +/- 3.0 vs CON 6.7 +/- 2.5, NS). On 2 subsequent tests patients received N (0.2 mg/kg) or P intravenously and chest pain was evaluated on an analogue scale (score from 1 to 10). After N compared to P we observed: an increased perception of chest pain in SYM (6.8 +/- 1.5 vs 4.2 +/- 1.0; p less than 0.01) without significant changes of the ischemic threshold (total work, heart rate-blood pressure product, ST segment changes, 2D-echocardiographic wall motion abnormalities); no modifications in ASYM and CON.(ABSTRACT TRUNCATED AT 250 WORDS)
Fedele
F
F
Fisiopatologia Cardiovascolare, Università degli Studi, L'Aquila, Roma.
Benedetti
G
G
Vizza
C D
CD
Agati
L
L
Penco
M
M
Barletta
C
C
Scavo
D
D
Dagianti
A
A
D000368:Aged; D003327:Coronary Disease / Q000503:physiopathology*; D004311:Double-Blind Method; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009270:Naloxone; D010147:Pain Measurement; D001615:beta-Endorphin / Q000097:blood / Q000502:physiology*
D009270:Naloxone; D001615:beta-Endorphin