Substance P, acetylcholinesterase, and β-endorphin levels in the plasma and pericardial fluid of patients with and without angina pectoris

We measured substance P-like immunoreactivity (SPLI), β-endorphin-like immunoreactivity (BELI), acetylcholinesterase activity, and total protein content in pericardial fluid and plasma of patients with angina pectoris and patients with no angina pectoris. SPLI and BELI levels, acetylcholinesterase activity, and total protein content were determined by radioimmunoassay, a colorimetric method, and by the method of Lowry et al. (J Biol Chem 1951; 193: 265-275), respectively. In the pericardial fluid, patients with angina had SPLI, BELI, acetylcholinesterase, and total protein values of 1.69 ± 0.23 fmol/mg protein, 0.16 ± 0.13 fmol/mg protein, 0.06 ± 0.02 units, and 25.7 ± 3.2 mg/ml, respectively. Patients with no angina had SPLI, BELI, acetylcholinesterase, and total protein values of 0.93 ± 0.17 fmol/mg protein, 0.19 ± 0.10 fmol/mg protein, 0.16 ± 0.02 units, and 44.6 ± 5.3 mg/ml, respectively. SPLI levels were significantly higher (p < 0.03), and acetylcholinesterase (< 0.002) and total protein content (< 0.004) were significantly lower in the pericardial fluid of patients with angina when compared with those of patients with no angina. BELI levels were not significantly different between the two groups. In the plasma, no significant differences were found in SPLI, BELI, acetylcholinesterase, and total protein values between the two groups of patients. Patients with angina had SPLI, BELI, acetylcholinesterase, and total protein values of 0.47 ± 0.26 fmol/mg protein, 0.06 ± 0.06 fmol/mg protein, 0.29 ± 0.15 units, and 68.2 ± 8.7 mg/ml, respectively. Patients with no angina had SPLI, BELI, acetylcholinesterase, and total protein values of 0.45 ± 0.08 fmol/mg protein, 0.07 ± 0.06 fmol/mg protein, 0.26 ± 0.08 units, and 70.9 ± 13.7 mg/ml, respectively. Our results may suggest that increased SPLI levels in the pericardial fluid reflect an increase in SP levels in the heart, which may be responsible for some of the symptoms, including angina, in patients with coronary ischemia.

Duke Scholars

Author Winston Clive Victor Parris Anesthesiology, Pain Management