Diazoxide protects the rabbit heart following cardioplegic ischemia

Jun Feng, Hongling Li, Eliot R. Rosenkranz

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

KATP channels are present in sarcolemmal and mitochondrial membranes. This study tests the hypothesis that opening mitochondrial KATP channels with Diazoxide (DZ) improves tolerance to cardioplegic ischemia during surgery. Twenty-two rabbit hearts were perfused with Krebs-Henseleit buffer (KHB) on a Langendorff apparatus and underwent 50 min of 37°C global ischemia with St Thomas' cardioplegia (STCP). Hearts were divided into three groups. Ten (control) received no pretreatment. Seven (DZ) received 10 min of 30 μM DZ, a selective mitochondrial KATP opener, in KHB before arrest with STCP containing 30 μM DZ. Five (5-HD + DZ) received 10 min of 100 μM sodium 5-hydroxydecanoate (5-HD), a selective mitochondrial KATP channel blocker, followed by 10 min of 30 μM DZ and 100 μM 5-HD in KHB before arrest with STCP + 30 μM DZ + 100 μM 5-HD. LV developed pressure (LVDP), dP/dt and coronary flow (CF) were measured after 60 min of reperfusion. Diazoxide pretreatment significantly improved the recovery of LV function and coronary flow compared to control (LVDP: 49 ± 5* vs. 31 ± 4; +dP/dtmax 927 ± 93 vs. 507 ± 85 mmHg/sec*; CF 33 ± 4 vs. 22 ± 2 ml/min, *p < 0.05). Mitochondria KATP channel blockade with 5-HD prevented DZ's salutary effect on the recovery of LV and vascular function. Diazoxide pretreatment protects the rabbit heart during cardioplegic ischemia by opening mitochondrial KATP channels. Opening mitochondrial KATP channels may be a new strategy for improving myocardial protection during cardiac surgery.

Original languageEnglish (US)
Pages (from-to)133-138
Number of pages6
JournalMolecular and Cellular Biochemistry
Volume233
Issue number1-2
DOIs
StatePublished - Jan 1 2002

Keywords

  • Cardioplegia
  • Diazoxide
  • Mitochondrial K channel
  • Preconditioning
  • Rabbit

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology

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