Intracellular magnesium homeostasis is involved in the functional recovery of preconditioned rat heart.
The role of ionic derangements in preconditioned hearts (PC) was assessed by measuring pHi, high-energy phosphates (HEP) and [Mg2+] by 31P NMR. Control (C) Langendorff rat hearts were subjected to 30' ischemia and 30' reflow. PC underwent 4x(2' ischemia + 3' reperfusion) before prolonged ischemia and reflow. In this model, the contractile recovery of PC hearts at the end of reflow (rate-pressure product RPP: 50 +/- 12% vs. 5 +/- 5% of C, p = 0.004) is not related to higher HEP or pHi levels than in C. [Mg2+]i increased significantly during ischemia both in C and PC organs; upon reperfusion its level remained significantly high in C (p < 0.001), while it regained the normal value in PC hearts. This behavior might improve in turn the SR calcium handling in PC organs, eventually contributing to the contractile recovery.
Bradamante
S
S
CNR, Centro Speciali Sistemi Organici, University of Milan, Italy.
de Jong
J W
JW
Piccinini
F
F
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D004734:Energy Metabolism; D006321:Heart / Q000502:physiology*; D006339:Heart Rate; D006706:Homeostasis; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008274:Magnesium / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009200:Myocardial Contraction; D017202:Myocardial Ischemia / Q000378:metabolism; D015425:Myocardial Reperfusion; D010710:Phosphates / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D010710:Phosphates; D010725:Phosphocreatine; D000255:Adenosine Triphosphate; D008274:Magnesium