@article {Consolini:2011:0008-4212:485,
title = "Mitochondrial and cytosolic calcium in rat hearts under high-K+ cardioplegia and pyruvate: mechano-energetic performance",
journal = "Canadian Journal of Physiology and Pharmacology",
parent_itemid = "infobike://cndscipub/cjpp",
publishercode ="cndscipub",
year = "2011",
volume = "89",
number = "7",
publication date ="2011-07-27T00:00:00",
pages = "485-496",
itemtype = "ARTICLE",
issn = "0008-4212",
eissn = "1205-7541",
url = "https://www.ingentaconnect.com/content/cndscipub/cjpp/2011/00000089/00000007/art00004",
doi = "doi:10.1139/y11-042",
keyword = "cœur, pyruvate, Rhod-2, Ca2+, calorimetry, cardiomyocytes, heart, cardioplegia, Fura-2, cardioplégie, calorimétrie",
author = "Consolini, A.E. and Ragone, M.I. and Bonazzola, P.",
abstract = "High-K+-cardioplegia (CPG) and pyruvate (Pyr) are used as cardioprotective agents. Considering that mitochondria play a critical role in cardiac dysfunction, we investigated the effect of CPG on mitochondrial Ca2+ uptake and sarcorreticular (SR) calcium handling.
Cytosolic and mitochondrial Ca2+, as well as mitochondrial membrane potential (m) were assessed in rat cardiomyocytes by confocal microscopy. Mechano-calorimetrical correlation was studied in perfused hearts. CPG did not modify JC-1 (m), but transiently increased,
by up to 1.8 times, the Fura-2 (intracellular Ca concentration, [Ca2+]i) and Rhod-2 (mitochondrial free Ca concentration [Ca2+]m) fluorescence of resting cells, with exponential decays. The addition of 5\textmumol\textperiodcenteredL1 thapsigargin (Tpg) increased
the Rhod-2 fluorescence in a group of cells without any effect on the Fura-2 signal. In rat hearts perfused with CPG, 1\textmumol\textperiodcenteredL1 Tpg decreased resting heat rate (H
r:0.44\textpm 0.07mW\textperiodcenteredg1),
while the addition of 5\textmumol\textperiodcenteredL1 KB-R7943 increased resting pressure (rLVP by+5.26\textpm 1.10mm Hg; 1mm Hg= 133.322 Pa). The addition of 10mmol\textperiodcenteredL1 Pyr to CPG increased H
r
(+3.30\textpm 0.24mW\textperiodcenteredg1) and rLVP (+2.2\textpm 0.4mm Hg), which are effects potentiated by KB-R7943. The results suggest that under CPG, (i) there was an increase in [Ca2+]i and [Ca2+]m (without changing m)
that decayed by exothermic removal mechanisms; (ii) mitochondrial Ca2+ uptake contributed to the removal of cytosolic Ca2+, in a process that was potentiated by inhibition of sarcoendoplasmic reticulum Ca2+-ATPase (SERCA), and reduced by KB-R7943;
(iii) under these conditions, SERCA represents the main energetic consumer; (iv) Pyr increased the energetic performance of hearts,mainly by inducing mitochondrial metabolism.",
}