Metabolic changes associated with acid-base regulation during hypercarbia in the CO2-tolerant chondrostean, white sturgeon (Acipenser transmontanus)
Metabolic changes associated with acid-base regulation during hypercarbia in the CO2-tolerant chondrostean, white sturgeon (Acipenser transmontanus)
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DOI：
10.1016/j.cbpa.2011.09.002
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发表时间：
2012-01-01
影响因子：
2.3
通讯作者：
Brauner, Colin J.
中科院分区：
文献类型：
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作者：
Baker, Daniel W.;Brauner, Colin J.
白色鲟鱼的CO2耐受性与严格调节细胞内pH（pHi）的能力相关，尽管细胞外pH（pHe）大幅降低，称为优先pHi调节。这种调节反应如何影响整个动物的代谢率尚不清楚。因此，我们的特点耗氧率（（O2））和代谢相关的有机体和细胞反应在白色鲟鱼在暴露于高碳酸盐。白色鲟鱼能够保护细胞内的pH值（pHi）在肝脏和白色肌肉早6小时（最早的时间段调查）暴露于严重（亚致死）高碳酸血症（45和90毫米汞柱PCO 2）。鲟鱼暴露于15和30毫米汞柱的PCO 2表现出pHe补偿和显着增加的M-O2（高达80%以上，比对照值）。相比之下，重度高碳酸血症（>= 45 mmHg PCO 2）引起pHe（高达1.0 pH单位）和红细胞（高达0.5 pH单位）的非代偿性降低，并分别伴有（O2）降低30%和60%。虽然观察到对高碳酸血症的行为、呼吸和细胞反应，但均与（O2）变化的模式或幅度不一致。这项研究的结果提供了实证支持的假设，优先pHi调节是不是代谢成本，因此可能是一种策略，强烈选择在鱼类遇到短期高碳酸血症。(C)2011 Elsevier Inc. All rights reserved.
CO2 tolerance in white sturgeon is associated with the ability to tightly regulate intracellular pH (pHi) despite a large reduction in extracellular pH (pHe) termed preferential pHi regulation. How this regulatory response affects whole animal metabolic rate is unknown. Accordingly, we characterized oxygen consumption rate ((O2)) and metabolically-relevant organismal and cellular responses in white sturgeon during exposure to hypercarbia. White sturgeon were able to protect intracellular pH (pHi) in liver and white muscle as early as 6 h (the earliest time period investigated) following exposure to severe (sub-lethal) hypercarbia (45 and 90 mmHg PCO2). Sturgeon exposed to 15 and 30 mmHg PCO2 exhibited pHe compensation and significant increases in M-O2 (up to 80% greater than control values). In contrast severe hypercarbia (>= 45 mmHg PCO2) elicited an uncompensated reduction in pHe (up to similar to 1.0 pH units) and red blood cells (as great as similar to 0.5 pH units), and was accompanied by 30 and 60% reductions in (O2), respectively. While behavioral, respiratory and cellular responses to hypercarbia were observed, none corresponded well with the pattern or magnitude of changes in (O2). The findings of this research provide empirical support for the hypothesis that preferential pHi regulation is not metabolically costly, and thus may have been a strategy strongly selected for in fishes encountering short-term hypercarbia. (C) 2011 Elsevier Inc. All rights reserved.