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Analysis of angiotensin-stimulated sodium transport in cultured smooth muscle cells from rat aorta.
- Source :
-
Journal of cellular physiology [J Cell Physiol] 1983 Mar; Vol. 114 (3), pp. 284-90. - Publication Year :
- 1983
-
Abstract
- Angiotensin peptides (AI, AII, AIII) increased the rate of Na+ accumulation by smooth muscle cells (SMC) cultured from rat aorta. The stimulatory effect of AII on Na+ uptake was observed when Na+ exodus via the Na+/K+ pump was blocked either by ouabain or by the removal of extracellular K+. AII was at least ten times more potent than AIII and about 100 times more potent than AI in stimulating Na+ uptake. Saralasin had little effect on Na+ uptake by itself but almost completely blocked the increase caused by AII. The stimulation of net Na+ entry by AI, but not AII, was prevented by protease inhibitors. The stimulation of Na+ uptake was almost completely blocked by amiloride. Tetrodotoxin, which prevented veratridine from increasing Na+ uptake, had no effect on the response to AII. Angiotensin increased the rate of ouabain-sensitive 86Rb+ uptake (Na+/K+ pump activity) but had no effect on ouabain-sensitive ATPase activity in frozen-thawed SMC or in microsomal membranes isolated from cultured SMC. The stimulation of ouabain-sensitive 86Rb+ uptake by AII was blocked by saralasin. Omitting Na+ from the external medium prevented AII from increasing 86Rb+ uptake. AII had no effect on cell volume or cyclic AMP levels in the cultured SMC. These results suggest that angiotensin peptides activate an amiloride-sensitive Na+ transporter which supplies the Na+/K+ pump with more Na+, its rate-limiting substrate.
Details
- Language :
- English
- ISSN :
- 0021-9541
- Volume :
- 114
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Journal of cellular physiology
- Publication Type :
- Academic Journal
- Accession number :
- 6300146
- Full Text :
- https://doi.org/10.1002/jcp.1041140306