Effect of chronic left ventricular failure on beta-endorphin.
Stimulation of endogenous opiate secretion worsens circulatory dysfunction in several forms of shock, in part by inhibiting sympathetic activity. To investigate whether endogenous opiates have a similar effect in chronic heart failure (HF), we measured beta-endorphin concentrations and hemodynamic responses to naloxone infusion (2 mg/kg bolus + 2 mg.kg-1 x h-1) in six control (C) dogs and eight dogs with low-output HF produced by 3 wk of rapid ventricular pacing. The dogs with HF exhibited reduced arterial blood pressure (C, 123 +/- 4 vs. HF, 85 +/- 7 mmHg; P < 0.01) and cardiac outputs (C, 179 +/- 14 vs. HF, 76 +/- 2 ml.min-1 x kg-1; P < 0.01) and elevated plasma norepinephrine concentrations (C, 99 +/- 12 vs. HF, 996 +/- 178 pg/ml; P < 0.01) but normal beta-endorphin concentrations (C, 30 +/- 11 vs. HF, 34 +/- 12 pg/ml; P = NS). Naloxone produced similar transitory increases in blood pressure (C, 14 +/- 5 vs. HF, 26 +/- 25%) and cardiac output (C, 37 +/- 13 vs. HF, 22 +/- 15%) in both groups (both P = NS). No significant changes in norepinephrine concentration or systemic vascular resistance were observed in either group. These findings suggest that beta-endorphin secretion does not exacerbate circulatory dysfunction in chronic heart failure.
Mellow
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Cardiovascular Section, New York Hospital-Cornell Medical Center, New York 10021.
Redei
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Marzo
K
K
Wilson
J R
JR
D000324:Adrenocorticotropic Hormone / Q000097:blood; D000818:Animals; D002302:Cardiac Output / Q000187:drug effects; D002395:Catecholamines / Q000097:blood; D004285:Dogs; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000502:physiology; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D010101:Oxygen Consumption / Q000187:drug effects; D011669:Pulmonary Wedge Pressure / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects; D014694:Ventricular Outflow Obstruction / Q000097:blood*; D001615:beta-Endorphin / Q000097:blood*
D002395:Catecholamines; D009270:Naloxone; D001615:beta-Endorphin; D009020:Morphine; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone