Fowler, M.R., Orchard, C.H. and Harrison, S.M. (2007) Cellular distribution of calcium current is unaltered during compensated hypertrophy in the spontaneously hypertensive rat. Pflügers Archiv - European Journal of Physiology, 453(4), pp. 463-469. (doi: 10.1007/s00424-006-0147-5)
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Abstract
Changes in cellular calcium (Ca2+) handling are thought to underlie the altered contraction that occurs during cardiac hypertrophy and failure. Recent work has highlighted the importance of t-tubules in the control of intracellular Ca2+. The present study was performed to investigate whether changes in the distribution of I Ca between the surface and t-tubule membranes might contribute to the altered Ca2+ handling observed during compensated hypertrophy in the spontaneously hypertensive rat (SHR). Experiments were performed on ventricular myocytes isolated from 5-month-old SHR and normotensive Wistar-Kyoto (WKY) control rats. Osmotic shock using formamide was used to disrupt the t-tubular system and the whole-cell patch clamp technique used to monitor I Ca in the presence and absence of t-tubules. Membrane capacitance and I Ca were greater in control SHR than WKY myocytes; following detubulation, cell capacitance and I Ca both decreased and were no longer significantly different in the two cell types. The density of I Ca was not significantly different in control SHR and WKY cells or in detubulated myocytes from the two species. These data suggest that the distribution of I Ca is unchanged in SHR myocytes compared to WKY controls; I Ca density in the t-tubules was 1.2-fold greater than in the sarcolemma in both strains. These data also imply that the increase in surface area in SHR myocytes is due principally to an increase in t-tubular area, which is accompanied by an approximately equivalent increase in I Ca, so that the density of I Ca at the cell surface and in the t-tubules remains the same. These changes would be expected to retain cell function and synchronicity of Ca2+ release in the SHR at this stage of compensated hypertrophy.
| Item Type: | Articles |
|---|---|
| Status: | Published |
| Refereed: | Yes |
| Glasgow Author(s) Enlighten ID: | Fowler, Dr Mark |
| Authors: | Fowler, M.R., Orchard, C.H., and Harrison, S.M. |
| College/School: | College of Medical Veterinary and Life Sciences |
| Journal Name: | Pflügers Archiv - European Journal of Physiology |
| Publisher: | Springer-Verlag |
| ISSN: | 0031-6768 |
| ISSN (Online): | 1432-2013 |
| Published Online: | 26 October 2006 |
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