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Preconditioning in immature rabbit hearts: role of KATP channels. Circulation 1999 Mar 09;99(9):1249-54

Date

03/09/1999

Pubmed ID

10069795

DOI

10.1161/01.cir.99.9.1249

Scopus ID

2-s2.0-0033537664   64 Citations

Abstract

BACKGROUND: The protective effects of ischemic preconditioning have been shown to occur in adult hearts of all species studied. We determined whether immature hearts normoxic or chronically hypoxic from birth could be preconditioned, the time window or memory of the cardioprotective effect, and the involvement of the KATP channel.

METHODS AND RESULTS: Isolated immature rabbit hearts (7 to 10 days old) were subjected to 0, 1, or 3 cycles of preconditioning consisting of 5 minutes of global ischemia plus 10 minutes of reperfusion. This was followed by 30 minutes of global ischemia and 35 minutes of reperfusion. Normoxic hearts (FIO2=0.21) subjected to 1 cycle of preconditioning recovered 70+/-7% of left ventricular developed pressure compared with 43+/-8% recovery in nonpreconditioned controls. Three cycles of preconditioning did not result in additional recovery (63+/-8%). Hearts from rabbits raised from birth in hypoxic conditions (FIO2=0.12) and subjected to 1 and 3 preconditioning cycles did not show increased recovery (68+/-8% and 65+/-5%) compared with nonpreconditioned hypoxic controls (63+/-9%), although the recovery was greater in chronically hypoxic hearts than in age-matched normoxic controls. Increasing the recovery period after the preconditioning stimulus from 10 to 30 minutes resulted in a loss of cardioprotection. Pretreatment of normoxic hearts for 30 minutes with the KATP channel blocker 5-hydroxydecanoate (300 micromol/L) completely abolished preconditioning (70+/-7% to 35+/-9%) but had no effect on nonpreconditioned hearts (40+/-8%).

CONCLUSIONS: Immature hearts normoxic from birth can be preconditioned, whereas immature hearts hypoxic from birth cannot. Preconditioning in normoxic immature hearts is associated with activation of the KATP channel.

Author List

Baker JE, Holman P, Gross GJ

Author

John E. Baker PhD Professor in the Surgery department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Adenosine Triphosphate
Animals
Animals, Newborn
Anti-Arrhythmia Agents
Decanoic Acids
Hydroxy Acids
Hypoxia
In Vitro Techniques
Ischemic Preconditioning, Myocardial
Potassium Channels
Rabbits
Recovery of Function
Time Factors
jenkins-FCD Prod-482 91ad8a360b6da540234915ea01ff80e38bfdb40a