atrial-natriuretic-factor and dopexamine

In eight patients (63 +/- 8 years) with dilated cardiomyopathy, the acute effects of positive inotropic stimulation with dopexamine hydrochloride, a beta-2-agonistic and DA1-dopaminergic catecholamine, on the plasma levels of ANP and cGMP were tested. A four-point dose-response curve was prepared for dopexamine from 1 microgram/kg/min to 4 micrograms/kg/min. Each infusion stage lasted 15 min; ANP and cGMP were taken from the mixed venous blood. Hemodynamic parameters were determined by a Swan-Ganz catheter; cardiac output was determined by thermodilution. ANP dropped by 40% from 348 +/- 124 pg/ml to 208 +/- 70 pg/ml (p less than or equal to 0.01), while cGMP dropped by 25% from 4.8 +/- 1.6 pmol to 3.6 +/- 1.3 pmol/ml at the time of maximum hemodynamic effect after 1 h. Linear regression analyses revealed a significant relationship (p less than or equal to 0.01) between ANP as the independent variable and cGMP as the dependent variable. The hemodynamic determinants of the ANP concentration proved to be--independently of each other--the pulmonary capillary wedge pressure (p less than or equal to 0.01) and the mean right atrial pressure (p less than or equal to 0.01). The results show that chronically elevated ANP and cGMP levels can be strikingly reduced within a short time, whereby ANP and cGMP show similar kinetics. The results suggest a use of ANP and cGMP as humoral parameters in the therapy control of chronic heart failure.

Topics: Adrenergic beta-Agonists; Aged; Atrial Natriuretic Factor; Cardiomyopathy, Dilated; Clinical Trials as Topic; Cyclic GMP; Dopamine; Heart Failure; Hemodynamics; Humans; Infusions, Intravenous; Male; Middle Aged

Topics: Acute Kidney Injury; Atrial Natriuretic Factor; Blood Pressure; Cardiotonic Agents; Diuretics; Diuretics, Osmotic; Dopamine; Fenoldopam; Furosemide; Humans; Mannitol; Postoperative Complications; Vasodilator Agents

1. We have performed studies in rats with selective DA-1 receptor agonists fenoldopam and dopexamine which show that activation of tubular DA-1 receptors by these agents results in natriuresis and diuresis. 2. In pentobarbital-anaesthetized rats, an acute increase in sodium intake produced by volume expansion (5% body weight) with isotonic sodium chloride led to pronounced increases in sodium and water excretion. These natriuretic and diuretic responses were accompanied by significant increases in urinary dopamine excretion and could be attenuated by the selective DA-1 receptor antagonist, SCH 23390. 3. Intravenous infusion of atrial natriuretic factor produced hypotension, bradycardia and an increase in sodium and water excretion. The natriuretic and diuretic response to the peptide was not accompanied by any changes in urinary dopamine excretion but it was attenuated by SCH 23390 and the dopa decarboxylate inhibitor, carbidopa. 4. These results show that renal tubular DA-1 receptors can be activated by selective agonists, which subsequently leads to natriuresis and diuresis. During acute volume expansion, there is an increased production of renal dopamine, which contributes to the natriuretic response via activation of tubular DA-1 receptors. Finally, we discovered that endogenous dopamine plays a permissive role in the full expression of the renal effects of the atrial natriuretic factor.

Topics: 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; Animals; Atrial Natriuretic Factor; Dopamine; Dopamine Agents; Fenoldopam; Kidney; Kidney Tubules; Male; Natriuresis; Rats; Rats, Inbred Strains; Receptors, Dopamine; Receptors, Dopamine D1