Chronic administration of KB-R7943 induces up-regulation of cardiac NCX1

Lin Xu, Christiana S. Kappler, Santhosh K. Mani, Neal R. Shepherd, Ludivine Renaud, Paige Snider, Simon J. Conway, Donald R. Menick

Research output: Contribution to journalArticle

10 Scopus citations


The NCX1 (sodium-calcium exchanger) is up-regulated in human heart failure and in many animal models of heart failure. The potential benefits and risks of therapeutically blocking NCX1 in heart failure and during ischemia-reperfusion are being actively investigated. In this study, we demonstrate that prolonged administration of the NCX1 inhibitor KB-R7943 resulted in the up-regulation of Ncx1 gene expression in both isolated adult cardiomyocytes and intact mouse hearts. Ncx1 up-regulation is mediated by the activation of p38. Importantly, p38 is not activated by KB-R7943 treatment in heart tubes from Ncx1-/- mice at 9.5 days postcoitum but is activated in heart tubes from Ncx1-/- mice. p38 activation does not appear to be in response to changes in cytosolic calcium concentration, [Ca2+]i. Interestingly, chronic KB-R7943 treatment in mice leads to the formation of an NCX1-p38 complex. Our study demonstrates for the first time that the electrogenic sarcolemma membrane cardiac NCX1 can act as a regulator of "activity-dependent signal transduction" leading to changes in gene expression.

Original languageEnglish (US)
Pages (from-to)27265-27272
Number of pages8
JournalJournal of Biological Chemistry
Issue number40
StatePublished - Oct 2 2009

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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    Xu, L., Kappler, C. S., Mani, S. K., Shepherd, N. R., Renaud, L., Snider, P., Conway, S. J., & Menick, D. R. (2009). Chronic administration of KB-R7943 induces up-regulation of cardiac NCX1. Journal of Biological Chemistry, 284(40), 27265-27272.