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Cardiology Research and Practice
Volume 2012, Article ID 986813, 9 pages
http://dx.doi.org/10.1155/2012/986813
Research Article

Endothelin-B Receptors and Left Ventricular Dysfunction after Regional versus Global Ischaemia-Reperfusion in Rat Hearts

1Department of Pharmaceutical Chemistry, University of Athens School of Pharmacy, University Campus, Zografou, Athens 15771, Greece
2Cardiovascular Research Institute, Zoodoxos, Ioannina 45500, Greece
3Department of Cardiology, University of Ioannina, 1 Stavrou Niarxou Avenue, Ioannina 45110, Greece
4Department of Cardiology, University Hospital, 55 Hufelandstrasse, Essen 45122, Germany
5Experimental Research Center ELPEN, 95 Marathonos Avanue, Pikermi, Athens 19009, Greece
6Department of Cardiology, Athens Red Cross Hospital, 1 Erythrou Stavrou Street, Athens 11526, Greece

Received 1 May 2012; Revised 23 May 2012; Accepted 1 June 2012

Academic Editor: Yasuo Matsumura

Copyright © 2012 Sofia-Iris Bibli et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background. Endothelin-1 (ET-1) is implicated in left ventricular dysfunction after ischaemia-reperfusion. ETA and ETB receptors mediate diverse actions, but it is unknown whether these actions depend on ischaemia type and duration. We investigated the role of ETB receptors after four ischaemia-reperfusion protocols in isolated rat hearts. Methods. Left ventricular haemodynamic variables were measured in the Langendorff-perfused model after 40- and 20-minute regional or global ischaemia, followed by 30-minute reperfusion. Wild-type (n=39) and ETB-deficient (n=41) rats were compared. Infarct size was measured using fluorescent microspheres after regional ischaemia-reperfusion. Results. Left ventricular dysfunction was more prominent in ETB-deficient rats, particularly after regional ischaemia. Infarct size was smaller (P=0.006) in wild-type (31.5±4.4%) than ETB-deficient (45.0±7.3%) rats after 40 minutes of regional ischaemia-reperfusion. Although the recovery of left ventricular function was poorer after 40-minute ischaemia-reperfusion, end-diastolic pressure in ETB-deficient rats was higher after 20 than after 40 minutes of regional ischaemia-reperfusion. Conclusion. ETB receptors exert cytoprotective effects in the rat heart, mainly after regional ischaemia-reperfusion. Longer periods of ischaemia suppress the recovery of left ventricular function after reperfusion, but the role of ETB receptors may be more important during the early phases.