Premium
Effect of the Na + /H + antiport inhibitor Hoe 694 on the angiotensin II‐induced vascular smooth muscle cell growth
Author(s) -
Sachinidis Agapios,
Seul Claudia,
Ko Yon,
Düsing Rainer,
Vetter Hans
Publication year - 1996
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1996.tb15741.x
Subject(s) - angiotensin ii , antiporter , amiloride , cytosol , sodium–hydrogen antiporter , intracellular , chemistry , cell growth , intracellular ph , vascular smooth muscle , microbiology and biotechnology , biochemistry , endocrinology , biology , sodium , enzyme , receptor , organic chemistry , membrane , smooth muscle
1 Hoe 694 (3‐methylsulphonyl‐4‐piperidinobenzoyl)guanidine methanesulphonate) was characterized as a new, potent, non‐amiloride inhibitor of the Na + /H + exchanger. In order to elucidate the role of the Na + /H + exchanger isoform 1 (NHE‐1) in the regulation of vascular smooth muscle cell growth, we investigated the effects of different amiloride analogues and of Hoe 694 on angiotensin II‐induced cell growth. Since intracellular pH, the intracellular free Ca 2+ concentration and the expression of the transcription factor c‐fos seem to be involved in the regulation of cell growth, the effects of the amiloride analogues and Hoe 694 on the angiotensin II‐induced changes in these three parameters were examined. 2 Measurement of cytosolic Ca 2+ and pH in cell monolayers was performed using fura‐2/AM and BCECF/AM, respectively. The effect of angiotensin II on cell growth was examined using (1) [ 3 H]‐thymidine incorporation, (2) the bromo‐2‐deoxyuridine (BrdU) immunfluorescence assay, (3) the colorimetric determination of cell mitochondrial dehydrogenase activity and (4) determination of cell number. Total RNA was extracted from cells by the guanidinium isothiocyanate/CsCl procedure. The expression of c‐fos was quantitated by Northern blotting. 3 Various amiloride analogues inhibited the angiotensin II‐induced stimulation of the Na + /H + exchanger, the increase in cytosolic Ca 2+ and cell growth but not the induction of c‐fos mRNA. Hoe 694 (1–25 μ m ) dose‐dependently inhibited the angiotensin II‐induced stimulation of the Na + /H + exchanger but had no significant effects on cytosolic Ca 2+ , c‐fos mRNA levels or cell growth. 4 Our findings support the concept that activation of the Na + /H + exchanger is not essential for angiotensin II‐induced vascular smooth muscle cell growth.