Abstract
Although several studies have shown that vanadate evokes vasoconstriction whether it elevates cytosolic free calcium, [Ca2+]i, in vascular smooth muscle (VSM) cells has not been investigated. The present study shows that acute additions of low concentrations of vanadate (10-200) to cultured aortic smooth muscle cells (ASMC) produced a rapid and a concentrationdependent increase in [Ca2+]i with an EC50 (mean ± SEM) value of 42 ± 11 μM. Inclusion of vanadate (200 μM) led to a significant increase (p < 0.05) in the peak [Ca2+]i level to 190 ± 23 nM from a basal level of 102 ± 2 nM. At concentrations > 200 μM, vanadate caused quenching of fura-2 fluorescence. For example, addition of 1 mM vanadate led to an apparent decrease in fluorescence by about 50 % (due to a quenching effect), followed by a transient rise. H2O2, which is used in the preparation of peroxide forms of vanadate, pervanadate (PV), also produced a rise in [Ca2+]i. These data suggest that vanadate promotes vascular tone by elevating [Ca2+]i in ASMC. However, [Ca2+]i measurements made with higher concentrations of vanadate and PV, using the fura-2 method, must be interpreted with caution.
Original language | English (US) |
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Pages (from-to) | PL169-PL174 |
Journal | Life Sciences |
Volume | 56 |
Issue number | 7 |
DOIs | |
State | Published - Jan 6 1995 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- General Biochemistry, Genetics and Molecular Biology
- General Pharmacology, Toxicology and Pharmaceutics