Inhibition by antisense oligonucleotides of plasma membrane Ca(2+) ATPase in vascular endothelial cells.

Antisense oligodeoxynucleotides were used to knock down plasma membrane Ca(2+) ATPase, and the role of plasma membrane Ca(2+) ATPase was investigated in human aortic endothelial (HAE) cells. The peak of thapsigargin-evoked intracellular Ca(2+) concentration ([Ca(2+)](i)) was higher in antisense-treated than in untreated cells, but the declining time course was unaffected by the antisense treatment. The declining time was prolonged in both antisense-treated and untreated cells by reducing external Na(+), but the prolongation was more marked in the antisense-treated cells. These results provide the evidence of a functional role of plasma membrane Ca(2+) ATPase, although other mechanisms including Na(+)/Ca(2+) exchange may play the primary role in regulating [Ca(2+)](i).