El intercambiador Na+/Ca2+ como responsable del atontamiento miocardico

Translated title of the contribution: The Na+/Ca2+ exchanger as a culprit of myocardial stunning

Susana M. Mosca, Horacio E. Cingolani

Research output: Contribution to journalArticlepeer-review

Abstract

Our objective was to assess the participation of Na+/H+ exchanger (NHE) and Na+/Ca2+ exchanger (NCX) on systolic and diastolic alterations of myocardial stunning. Isolated perfused rat hearts were submitted to 20 min of global ischemia (Is) followed by 30 min of reperfusion (R). This protocol was repeated after treatment before ischemia and/or early in R. with HOE 642 1μM, a specific blocker of NHE-1 and KB-R7943 1 & mu;M the novel inhibitor of the reverse mode of NCX. In control ischemic hearts the contractility assessed through +dP/dtmax recovered approximately 60%. When the NHE blockade was performed before Is or early in R the postischemic recovery reached 100%. The blockade of the reverse mode of NCX only improved significantly the recovery when administered before Is and early in R (95 & plusmn; 7%). The ischemic contracture decreased when the treatment with both blockers was performed before Is. During R the increase of end diastolic pressure (EDP) observed in control ischemic hearts (at 30 min of R, EDP value was 44 & plusmn; 4 mmHg) diminished significantly by NHE (24 & plusmn; 6 and 12 & plusmn; 2 mmHg when the blocker was administered before or after Is) and NCX blockade performed before and after Is (12 & plusmn; 6 mmHg). These results indicate that the activation of the reverse mode of NCX secondary to the NHE activation during ischemia and reperfusion is the mechanism responsible for the Ca2+ overload involved in the diminution of contractility that characterizes myocardial stunning.

Translated title of the contributionThe Na+/Ca2+ exchanger as a culprit of myocardial stunning
Original languageSpanish
Pages (from-to)167-173
Number of pages7
JournalMedicina
Volume61
Issue number2
StatePublished - Dec 1 2001

Keywords

  • Ischemia
  • Myocardial stunning
  • Na/ca blockade
  • Na/h blockade

ASJC Scopus subject areas

  • Medicine(all)

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