title: Effect of congestive heart failure on rate of atrial natriuretic factor release in response to stretch and isoprenaline.
abstract: OBJECTIVE
  The aim was to investigate the pattern of release of atrial natriuretic factor induced by mechanical and adrenergic stimulation from atria of rats with or without congestive heart failure.
  
  
  METHODS
  Monocrotaline, a pyrrolizidine alkaloid, was given to rats to cause severe pulmonary hypertension, leading to a marked degree of right ventricular hypertrophy and failure. Measurements of noradrenaline and atrial natriuretic factor were performed in each cardiac chamber and in plasma. Right and left atria of control rats and rats with congestive heart failure were isolated and subjected to mechanical or adrenergic stimulation to study the in vitro release of atrial natriuretic factor.
  
  
  METHODS
  Studies were performed on plasma, ventricles, and isolated right and left atria of 276 male Wistar rats, 80-100 g weight, with or without congestive heart failure.
  
  
  RESULTS
  In monocrotaline rats right and left ventricular concentrations of noradrenaline were significantly reduced. In the same rats concentrations of atrial natriuretic factor fell to 15.2% in the right atria and to 65.5% in the left atria. Whole heart content of atrial natriuretic factor was diminished, while plasma concentrations were increased sevenfold. Isolated hypertrophied right atria of failing hearts did not release atrial natriuretic factor in response to stretch or to isoprenaline (10(-9)M) and they were insensitive to the inotropic action of isoprenaline. On the other hand, non-hypertrophied left atria from the same animals released increased amounts of atrial natriuretic factor under basal conditions and after both stimuli, despite reduced tissue stores of the peptide.
  
  
  CONCLUSIONS
  Heart failure may deplete cardiac stores of noradrenaline and atrial natriuretic factor, especially in hypertrophied chambers, and can result in a decrease in the release of atrial natriuretic factor from atrial tissue in response to mechanical and adrenergic stimulation.
authors: Cattedra di Cardiologia, Università degli Studi di Brescia, Italy.
authors: G
authors: G
authors: Agnoletti
authors: A
authors: A
authors: Cornacchiari
authors: A F
authors: AF
authors: Panzali
authors: S
authors: S
authors: Ghielmi
authors: F
authors: F
authors: De Giuli
authors: R
authors: R
authors: Ferrari
mesh_terms: D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D006325:Heart Atria / Q000187:drug effects; D006333:Heart Failure / Q000139:chemically induced / Q000378:metabolism*; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology*; D008297:Male; D016686:Monocrotaline; D009200:Myocardial Contraction / Q000502:physiology; D009206:Myocardium / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism; D009929:Organ Size; D010947:Plants, Toxic; D011763:Pyrrolizidine Alkaloids; D051381:Rats; D011919:Rats, Inbred Strains; D012674:Senecio; D013997:Time Factors
chemical_list: D011763:Pyrrolizidine Alkaloids; D016686:Monocrotaline; D009320:Atrial Natriuretic Factor; D007545:Isoproterenol; D009638:Norepinephrine