Urotensin II-Induced Increase in Myocardial Distensibility Is Modulated by Angiotensin II and Endothelin-1

• Type: Article in International Scientific Journal
• Date: 2009

Authors

Fontes-Sousa AP (Author) Other; Pires AL (Author) Other; Monteiro-Cardoso VF (Author) Other; Leite-Moreira AF (Author) FMUP

Journal

Title: Physiological Research

Vol. 58 No. 5

Pages: 653-660

ISSN: 0862-8408

Publisher: Akademie Ved Ceske Republiky

Indexing

ISI Web of Knowledge - 10 Citations

Scopus - 12 Citations

Scientific classification

FOS: Medical and Health sciences > Other medical sciences

Other information

Authenticus ID: P-003-RNW

Abstract (EN): Endogenous regulators, such as angiotensin-II (AngII), endothelin-1 (ET-1) and urotensin-II (U-II) are released from various cell types and their plasma levels are elevated in several cardiovascular diseases. The present study evaluated a potential crosstalk between these systems by investigating if the myocardial effects of U-II are modulated by AngII or ET-1. Effects of U-II (10(-8), 10(-7), 10(-6) M) were tested in rabbit papillary muscles in the absence and in the presence of losartan (selective AT, receptor antagonist), PD-145065 (nonselective ET-1 receptors antagonist), losartan plus PD-145065, AngII or ET-1. U-II promoted concentration-dependent negative inotropic and lusitropic effects that were abolished in all experimental conditions. Also, U-II increased resting muscle length up to 1.008 +/- 0.002 L/L(max). Correcting it to its initial value resulted in a 19.5 +/- 3.5 % decrease of resting tension, indicating increased muscle distensibility. This effect on muscle length was completely abolished in the presence of losartan and significantly attenuated by PD-145065 or losartan plus PD-145065. This effect was increased in the presence of AngII, resulting in a 27.5 +/- 3.9 % decrease of resting tension, but was unaffected by the presence of ET-1. This study demonstrated an interaction of the U-II system with the AngII and ET-1 systems in terms of regulation of systolic and diastolic function.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8