Endothelial dysfunction underlying the increased contractility in aorta from older rats.

Dileep Kumar Rohraab; Hina Saeed Zubairib; Yasushi Ohizumia

Author(s)

Dileep Kumar Rohraab Department of Pharmaceutical Molecular Biology, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba, Aramaki, Aoba -ku, Sendai, 980-8578, Japan; Department of Biological and Biomedical Sciences, Faculty of Health Sciences, Aga Khan University, Karachi. Pakistan

Hina Saeed Zubairib Department of Biological and Biomedical Sciences, Faculty of Health Sciences, Aga Khan University, Karachi, Pakistan

Yasushi Ohizumia Department of Pharmaceutical Molecular Biology, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba, Aramaki, Aoba -ku, Sendai, 980-8578, Japan

Abstract

Background: Aging is associated with marked changes in the cardiovascular system and is one of the most important independent risk factors for cardiovascular diseases. The purpose of this study was to elucidate whether smaller increases in age influences the vascular contractile effect of various stimuli in rat thoracic aorta. An additional aim was evaluate the contribution of vascular smooth muscle and endothelium in case there is an altered behavior of the contractility of the aorta in various age groups. Methods: Open rings of male Wistar rats of 7, 11 and 15 weeks were used in this study. The experiments were done in both endothelium-denuded as well as endotheliumintact preparations. Isometric contraction was measured by a force-displacement transducer. Results: KCl-induced contraction was not different in endothelium-denuded preparations from the three groups of animals, however, phenylephrine (PE), PGF2a and endothelin-1 (ET-1) produced an exaggerated contractile response in aorta from 15 week animals. Carbachol relaxed the contraction produced by PE in a concentration-dependent manner; however the magnitude of relaxation was more marked in 7 week animals compared to that in 11 or 15 week rats. Conclusion: Our study shows for the first time that even a modest increase in age from 7 to 15 weeks produces changes in VSM as well endothelial cells resulting in exaggerated contractile response to agonists.

Publication Details

Page(s) 8-11

DOI DOI not available

Published Journal: Pakistan Journal of Physiology, Volume: 2, Issue: 2, Year: 2006

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