Abstract
Endothelin-1 (ET-1) not only causes potent vasoconstriction but also leads to fluid retention, both actions mediated by ET(A)- and/or ET(B)-receptors. Selective ET(A)- and combined ET(A)/ET(B)-receptor antagonists improve hemodynamics in heart failure; however, it is also important to evaluate the effects of these antagonists on urine output in heart failure. We administered an acute dose of either the selective ET(A)-receptor antagonist FR139317 (FR, n=5, 1 and 3 mg/kg) or the mixed ET(A)/ET(B)-receptor antagonist TAK-044 (TAK, n = 5, 1 and 3 mg/kg) to dogs with heart failure induced by rapid ventricular pacing. Renal hemodynamic and tubular functions were subsequently investigated. FR increased urinary excretion in association with increased renal plasma flow (RPF) and glomerular filtration rate (GFR) with no significant changes in the fractional reabsorption of water distally (FRWD). In contrast, despite increased GFR, TAK did not alter urine volume or RPF with significantly increased FRWD. The increase of GFR and RPF induced by FR was significantly larger than that of TAK. These findings indicate that ET(B)-receptor activation may result in diuresis by renal vasodilatation and reduction of water reabsorption in the distal tubules and collecting ducts. Acute ET(A)-receptor antagonism may therefore be more beneficial to diuresis than dual ET(A)/ET(B)-receptor inhibition in heart failure.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.