dynorphins and Heart-Failure

The aim of our study was to evaluate the effects of endogenous opioids on the secretion of atrial natriuretic factor (ANF) in moderate chronic heart failure (HF).. We evaluated the effects of i.v. volume load (NaCl 0.9% at 0.25 ml/Kg/min for 60 minutes) on heart rate (HR), on mean arterial pressure (MAP) and on the plasma levels of beta-endorphin (beta-end), met-enkephalin (Met-enk), dynorphin (Dyn), atrial natriuretic factor (ANF) and noradrenaline (NA) in 10 patients (age 58 +/- 9) with HF in NYHA class II (group I) and in 8 healthy control subjects (age 54 +/- 10) group II). The volume load was repeated after at least three days during infusion of naloxone (2 micrograms/Kg/min), evaluating the above mentioned hemodynamic and hormonal parameters.. The acute volume expansion caused an increase in ANF concentration (from 51.7 +/- 19.7 to 67.4 +/- 36.9 pg/ml; p < 0.05) and in beta-end (from 11.9 +/- 5.3 to 16.6 +/- 7.5 fmol/ml; p < 0.05), In group I. In group II an isolated increase in ANF was observed (from 14.1 +/- 7.8 to 21.9 +/- 7.9 pg/ml; p < 0.02). No significant changes were detected for HR, MAP, Dyn, Met-enk and NA. In group I the percent increase of ANF is less than in group II (30 vs 55%; p < 0.05). The volume load infused during naloxone infusion caused a significant increase in HR (from 73 +/- 6 to 78 +/- 9 bpm; p < 0.05) and in NA (from 311 +/- 123 to 415 +/- 142 pg/ml; p < 0.05) In group I. In group II, an increase in ANF was detected (from 13.8 +/- 6.0 to 23.6 +/- 5.0 pg/ml; p < 0.01).. Our data suggest that in moderate HF beta-end stimulates the secretion of ANF and inhibits the activity of the sympatho-adrenergic system during acute volume expansion.

Topics: Adult; Aged; Analysis of Variance; Atrial Natriuretic Factor; beta-Endorphin; Chronic Disease; Data Interpretation, Statistical; Dynorphins; Enkephalin, Methionine; Female; Heart Failure; Hemodynamics; Humans; Male; Middle Aged; Naloxone; Narcotic Antagonists; Norepinephrine; Plasma Volume; Receptors, Adrenergic; Sodium Chloride; Sympathetic Nervous System

We evaluated plasma atrial natriuretic factor (ANF), beta-endorphin, met-enkephalin, dynorphin and noradrenaline levels in 20 healthy subjects and 20 acute congestive heart failure (CHF) patients. In all acute CHF patients plasma values of these hormones were higher than in healthy subjects. The hormonal pattern differed in patients with the more severe acute CHF (group 1) from patients with less severe acute CHF (group 2) (ANF 53.8 +/- 1.0 vs 34.6 +/- 1.5 pg.ml-1, noradrenaline 563.8 +/- 13.4 vs 202.4 +/- 10.6 pg.ml-1, met-enkephalin 41.0 +/- 3.2 vs 17.0 +/- 1.6 fmol.ml-1, dynorphin 46.8 +/- 3.7 vs 25.2 +/- 2.0 fmol.ml-1, P < 0.01; beta-endorphin 50.6 +/- 5.2 vs 41.8 +/- 4.1 fmol.ml-1,ns). Administration of an opioid antagonist (naloxone, 8 mg i.v.) did not modify ANF or noradrenaline concentration in healthy subjects. In group 1 naloxone administration significantly raised ANF (68.0 +/- 1.4 pg.ml-1), noradrenaline (776.6 +/- 18.7 pg.ml-1), blood pressure and heart rate, whereas in group 2 it significantly decreased ANF values (21.9 +/- 0.5 pg.ml-1) and did not modify the other parameters. Our findings suggest that the opioid system affects ANF release in acute CHF. In patients with severe CHF opioid peptides may attenuate ANF secretion reducing noradrenergic stimulation. On the other hand, when CHF is less severe and the sympathetic activity is moderate, opioid peptides may directly stimulate ANF secretion.

Topics: Acute Disease; Aged; Atrial Natriuretic Factor; beta-Endorphin; Case-Control Studies; Dynorphins; Enkephalin, Methionine; Female; Heart Failure; Hemodynamics; Humans; Male; Middle Aged; Naloxone; Norepinephrine