Seidelin M, Brauner C J, Jensen F B, Madsen S S
Institute of Biology, University of Southern Denmark-Main Campus, Odense University, Campusvej 55, DK-5230 Odense M, Denmark.
Zoolog Sci. 2001 Dec;18(9):1199-205. doi: 10.2108/zsj.18.1199.
Changes in branchial vacuolar-type H(+)-ATPase B-subunit mRNA and Na+, K(+)-ATPase alpha- and beta-subunit mRNA and ATP hydrolytic activity were examined in smolting Atlantic salmon exposed to hyperoxic and/or hypercapnic fresh water. Pre-smolts, smolts, and post-smolts were exposed for 1 to 4 days to hyperoxia (100% O2) and/or hypercapnia (2% CO2). Exposure to hypercapnic water for 4 days consistently decreased gill vacuolar-type H(+)-ATPase B-subunit mRNA levels. Salmon exposed to hyperoxia had either decreased or unchanged levels of gill B-subunit mRNA. Combined hyperoxia + hypercapnia decreased B-subunit mRNA levels, although not to the same degree as hypercapnic treatment alone. Hyperoxia generally increased Na+, K(+)-ATPase alpha- and beta-subunit mRNA levels, whereas hypercapnia reduced mRNA levels in presmolts (beta) and smolts (alpha and beta). Despite these changes in mRNA levels, whole tissue Na+, K(+)-ATPase activity was generally unaffected by the experimental treatments. We suggest that the reduced expression of branchial vacuolar-type H(+)-ATPase B-subunit mRNA observed during internal hypercapnic acidosis may lead to reduction of functional V-type H(+)-ATPase abundance as a compensatory response in order to minimise intracellular HCO3- formation in epithelial cells.
研究了暴露于高氧和/或高碳酸血症淡水环境中的大西洋鲑在洄游过程中鳃部液泡型H(+) -ATP酶B亚基mRNA、Na+、K(+) -ATP酶α和β亚基mRNA以及ATP水解活性的变化。将洄游前期、洄游期和洄游后期的鱼暴露于高氧(100% O2)和/或高碳酸血症(2% CO2)环境中1至4天。连续4天暴露于高碳酸血症水环境会持续降低鳃部液泡型H(+) -ATP酶B亚基mRNA水平。暴露于高氧环境中的鲑鱼鳃部B亚基mRNA水平降低或不变。高氧+高碳酸血症联合处理降低了B亚基mRNA水平，尽管程度不如单独的高碳酸血症处理。高氧通常会增加Na+、K(+) -ATP酶α和β亚基mRNA水平，而高碳酸血症会降低洄游前期(β)和洄游期(α和β)的mRNA水平。尽管mRNA水平发生了这些变化，但整个组织的Na+、K(+) -ATP酶活性通常不受实验处理的影响。我们认为，在体内高碳酸血症酸中毒期间观察到的鳃部液泡型H(+) -ATP酶B亚基mRNA表达降低可能导致功能性V型H(+) -ATP酶丰度降低，作为一种补偿反应，以尽量减少上皮细胞内HCO3-的形成。
