NKH477: A novel bronchodilator produces potentiation and tachyphylaxis reversal to salbutamol in isolated guinea pig trachea

✍ Scribed by Mariam H.M. Yousif; Olav Thulesius

• Book ID: 101265777
• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 126 KB
• Volume: 48
• Category: Article
• ISSN: 0272-4391
• DOI: 10.1002/(sici)1098-2299(199912)48:4<154::aid-ddr2>3.0.co;2-4

✦ Synopsis

The relaxant responses of the β 2 -adrenoceptor agonist salbutamol and NKH477, an activator of adenylate cyclase, were compared and the possible potentiating effect of NKH477 on salbutamol-induced bronchodilatation was measured together with the effectiveness of NKH477 in reversing tachyphylaxis development to salbutamol. The in vitro bronchodilator effect of salbutamol and NKH477 (10 -9 -10 -5 M) was measured on isolated guinea pig tracheal ring segments precontracted with carbachol (10 -6 M). Both salbutamol and NKH477 produced a concentration-dependent relaxation. EC 50 values were determined from cumulative concentration-response curves. Salbutamol was more potent than NKH477 in relaxing the tracheal preparations (7.1 ± 0.1 compared to 6.1 ± 0.2, respectively). NKH477 produced a significant increase in the salbutamolinduced bronchodilator effect. The potency values recorded for salbutamol were 7.1