Trifluoperazine effect on Na+ transport of the cultured vascular smooth muscle cell

S. Kuriyama, A. Aviv

Research output: Contribution to journalArticlepeer-review


Several studies have indicated that the Na+/H+ antiport can be stimulated via activation of the Ca2+ calmodulin system. Trifluoperazine (TFP) is a known calmodulin antagonist. The present study examines the use of this drug in delineating the role of the calmodulin system in activation of the Na+/H+ antiport of the vascular smooth muscle cell (VSMC). 22Na+ washout experiments and measurements of cellular Na+ concentration were performed in rat VSMCs subjected to 5-50 μM of TFP in the presence and in the absence of 1 mM amiloride or 1 mM ouabain. Cells subjected to TFP demonstrated a dose related, decline in the initial exchange rate constant (k(e)(i)) for 22Na+. This effect was distinguished from that of amiloride by the fact that amiloride did not exert any apparent influence on cellular Na+ concentration, whereas TFP increased the cellular concentration of the ion. Further experiments demonstrated that TFP inhibits Na+-K+-ATPase activity in VSMCs and that this effect is the primary cause for the drug-induced decline in the k(e)(i) for 22Na+. Thus, TFP cannot be used as a specific probe of the calmodulin system in the VSMC.

Original languageEnglish (US)
Pages (from-to)175-186
Number of pages12
JournalJikeikai Medical Journal
Issue number2
StatePublished - 1988
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Medicine


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