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Updated: Apr 30, 2026

Analysis of Tubular Membrane Networks in Cardiac Myocytes from Atria and Ventricles
Published on: October 15, 2014
Behavior of caveolae and caveolin-3 during the development of myocyte hypertrophy
Toshio Kikuchi1, Naoki Oka, Akimasa Koga
1Department of Internal Medicine III and Cardiovascular Research Institute, Kurume University School of Medicine, Kurume, Japan.
Abstract:
Recent studies have indicated that caveolae are enriched in a variety of signaling molecules, some of which are associated with cardiomyocyte hypertrophy. Caveolin-3, a major constituent of cardiac caveolae, has been suggested to interact with several signaling molecules. We investigated the morphologic changes of caveolae and caveolin-3 expression in hypertrophied cardiomyocytes induced by an alpha1-adrenergic agonist. Cultured rat neonatal cardiomyocytes were used for the experiments. Phenylephrine induced cellular hypertrophy associated with an increase of the number of caveolae and an up-regulation of caveolin-3. Although PMA increased the number of caveolae and the caveolin-3 expression, the extent of these up-regulations was less than that by phenylephrine. Moreover, ionomycin increased the number of caveolae and up-regulated caveolin-3 as much as phenylephrine. Phenylephrine-induced up-regulations of caveolae and caveolin-3 expression were inhibited by BAPTA, suggesting that the intracellular Ca2+ is involved in those regulations. Inhibitors of calcineurin and Ca2+calmodulin-dependent kinase II attenuated the phenylephrine-induced up-regulation of caveolin-3. In pressure-overloaded rat hearts, caveolin-3 protein levels were increased compared with sham-operated rats. In conclusion, the number of caveolae and the expression of caveolin-3 were up-regulated in rat hypertrophied cardiomyocytes, possibly via the alterations of intracellular Ca2+ and protein kinase C.
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