BRONCHODILATING EFFECTS OF NATRIURETIC AND VASORELAXANT PEPTIDES COMPARED TO SALBUTAMOL IN ASTHMATICS

In animal studies, the bronchial effects of urodilatin (URO, CDD/ANP-9 5-126, INN: ularitide) were superior to those of cardiodilatin/atrial natriuretic peptide (CDD, CDD/ANP-99-126). We compared the bronchodila ting properties of intravenous URO and CDD in 36 clinically stable ast hmatics showing a beta(2)-agonist-induced increase of the FEV(1) by gr eater than or equal to 15%. Any aerosol medication was discontinued fo r at least 8 h prior to the study. After baseline measurements of lung function parameters (FEV(1), VC, PEF, MEF(75), MEF(50), MEF(25)) an i ntravenous infusion of 5.7, 11.4 or 17.1 pmol/kg/min URO or CDD was ad ministered for 40 min in the morning. All measurements were repeated e very 10 min during the infusion, for 30 min thereafter, and after the inhalation of 1.25 mg salbutamol (SALE). Both peptides had significant effects. While 11.4 pmol/kg/min URO dilated the central airways (FEV( 1), PEF, MEF(75)) slightly more potently than the peripheral bronchiol es (MEF(50), MEF(25)), 17.1 pmol/kg/min URO was as effective as SALE a t all levels of the tracheobronchial tree. CDD reached only 50% of the SALE effect without a predominant localization of its action. The car diovascular parameters revealed a significantly stronger vasorelaxant activity of CDD. In conclusion, the dose-dependent bronchodilating pro perties of intravenous URO were significantly superior to those of CDD .