Characterization of enhanced 45Ca2+ efflux in cultured vascular smooth muscle cells from spontaneously hypertensive rats

Chen, S., Monteith, G.R. and Roufogalis, B.D. (1995) Characterization of enhanced 45Ca2+ efflux in cultured vascular smooth muscle cells from spontaneously hypertensive rats. American Journal of Hypertension, 8 10: 1015-1022.


Author Chen, S.
Monteith, G.R.
Roufogalis, B.D.
Title Characterization of enhanced 45Ca2+ efflux in cultured vascular smooth muscle cells from spontaneously hypertensive rats
Formatted title Characterization of enhanced 45Ca2+ efflux in cultured vascular smooth muscle cells from spontaneously hypertensive rats
Journal name American Journal of Hypertension   Check publisher's open access policy
ISSN 0895-7061
1941-7225
Publication date 1995-10
Sub-type Article (original research)
DOI 10.1016/0895-7061(95)00226-X
Volume 8
Issue 10
Start page 1015
End page 1022
Total pages 8
Place of publication Oxford, United Kingdom
Publisher Oxford University Press
Language eng
Formatted abstract In this study we have compared Ca2+ efflux in cultured aortic smooth muscle cells derived from male, 10-week-old spontaneously hypertensive and Wistar-Kyoto rats. The role of Ca2+-dependent protein kinase C and Ca2+ uptake in the regulation of the Ca2+ pump and Na+-Ca2+ exchange mediated Ca2+ efflux were investigated. Basal, angiotensin II, and ionomycin-stimulated Ca2+ effluxes were significantly higher in spontaneously hypertensive rats. Brief (5 min) or prolonged (3 h) incubation of the cells with 100 nmol/L 12-O-tetradecanoylphorbol-13-O-acetate (TPA), a protein kinase C stimulator, did not significantly affect the maximum Ca2+ efflux rate in either strain. However, the Ca2+ efflux rates at early timepoints in Wistar-Kyoto rats were increased by TPA, but not in spontaneously hypertensive rats. Incubation of cells with [45Ca]-labeled CaCl2 in balanced salt solution for 4 h led to greater Ca uptake in spontaneously hypertensive rats compared to Wistar-Kyoto controls. Verapamil (1 μmol/L) for 4 h reduced the cellular Ca content of spontaneously hypertensive rats by 30% to the level of Wistar-Kyoto rats; it also reduced the Ca content in Wistar-Kyoto rats, but to a lesser extent (18%). In parallel, Ca2+ efflux was also reduced by verapamil to a greater extent in spontaneously hypertensive rats than in Wistar-Kyoto rats. We conclude that Ca2+ efflux was enhanced in spontaneously hypertensive rats by a mechanism partly associated with greater Ca2+ uptake by a verapamil-sensitive pathway and possibly an alteration of protein kinase C regulation. However, an up-regulation of the number or efficiency of Ca2+ efflux sites may also significantly contribute as an adaptive response to enhanced Ca2+ influx.
Keyword Spontaneously hypertensive rats
CA2+ efflux
CA2+ pump
NA+-CA2+ exchange
Protein kinase C
Calcium
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Pharmacy Publications
 
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