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Protein kinase C regulates unloading contraction of cardiomyocytes in hypertrophic heart of spontaneously hypertensive rat

Wang Yunying, Yu Zhibin

Department of Aerospace Physiology, the Fourth Military Medical University.Xi'an 710032,Shaanxi

Abstract

The activation of protein kinase C (PKC) is not only a pivotal node during cardiac hypertrophy in chronic pressure-overloadedheart, but also involved in the regulation of cardiac contractility. The aim of this paper was to observe PKC modulation in cardiaccontractility at different stages of cardiac hypertrophy in spontaneously hypertensive rat (SHR). The cardiomyocytes were isolatedfrom 4- and 10-month-old normotensive Wistar-Kyoto (WKY) and SHR rat hearts. The shortening amplitude of unloading contractionin cardiomyocytes was observed by an Edge Detector system. The shortening amplitude in WKY rat cardiomyocytes increased graduallyas the stimulating frequency increased from 1 to 3 Hz. The shortening amplitude was positively correlated with stimulating frequency.The shortening amplitude in 4-month-old SHR group was enhanced as compared with that in WKY group at the same stimulatingfrequency. When the stimulating frequency increased, the shortening amplitude did not increase in 4-month-old SHR group. There wasno difference in shortening amplitude between 10-month-old SHR and WKY groups at 1-Hz stimulating frequency. But the shorteningamplitude in 10-month-old SHR group decreased when the stimulating frequency increased to 3 Hz. The perfusion of 50, 100 or 200nmol/L PMA (a non-specific agonist of PKCs) significantly reduced the shortening amplitude in WKY and SHR groups. The shorteningamplitude was reduced to (69.8±1.9)%, (58.23±2.2)% and (22.73±2.5)% (all P

Key words: cardiac hypertrophy;Protein kinase C;Cardiomyocyte;shortening amplitude

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Citing This Article：

Wang Yunying, Yu Zhibin. Protein kinase C regulates unloading contraction of cardiomyocytes in hypertrophic heart of spontaneously hypertensive rat. Acta Physiol Sin 2008; 60 (2): 197-204 (in Chinese with English abstract).