Conference Portal, 2018 International Conference on Pure and Applied Science

Font Size: 
Phosphodiesterase 5 Inhibitor Relaxes Isolated Rat Trachea in Endothelin-1 Induced Contraction
Ismail M. Maulood

##manager.scheduler.building##: Presidency Building Conference Hall
Date: 2018-04-24 09:40 AM – 10:00 AM
Last modified: 2018-08-16


Phosphodiesterase 5 inhibitor(PDE5) or sildenafil relaxes airway smooth muscle in endothelin-1 (ET-1) induces rat tracheal ring contraction, but the mysterious relationship between ET-1 and sildenafil unclear, therefore this study shows interactions of sildenafil with ET-1 and roles of ET-1 receptor antagonists on rat tracheal ring in ET-1 induced tracheal contraction. Rat tracheal rings (intact and denuded) isolated and transferred into organ chamber. The rings pre-incubated with the selective ET-1A receptor (BQ-123) and ET-1B receptor (BQ-788) antagonists, and then ET-1 dose-response curve (DRC) performed for the rat tracheal rings.  Pre-incubation of BQ-123 markedly reduced the ET-1 potency, while BQ-788 did not reduce ET-1 pD2; also in denuded isolated rat trachea rings, pre-incubated with BQ-123 changed Emax values. L-NAME pre-incubation increased sildenafil pD2,while indomethacin pre-incubation is slightly decreased sildenafilpD2, whereas clotrimazole pre-incubation significantly increased sildenafilpD2 and highly elevated of sildenafil maximum efficacy (Emax).In conclusions, ET-1 induces tracheal smooth muscles contraction due to ET-1A receptor activity rather than ET-1B receptor activity, and tracheal epithelial cells highly contributes in tracheal contraction. Sildenafil relaxes rat tracheal rings of ET-1 pre-contraction, mainly via the NO-dependent mechanism, inhibition of COX and cytochrome p450 epoxygenase (CYP)pathways.


Published 01 August 2018

DOI: 10.14500/icpas2018.bph52


Endothelin-1 receptors; Rats; Sildenafil; Trachea

Full Text: View the PDF File