盐度驯化对史氏鲟鳃Na^+/K^+-ATP酶活力、血清渗透压及离子浓度的影响

The influence of salinity acclimation on activity of Na^+/K^+-ATPase in branchial epithelium,concentration of ions and osmolarity in serum of Acipenser schrenckii

对史氏鲟在盐度驯化过程中鳃Na+/K+-ATP酶活力、血清渗透压及血清离子(Na+、K+、Cl-)浓度进行了检测和分析,探讨了史氏鲟驯化过程中血清渗透压调节机制。研究表明:史氏鲟在不同盐度(10、20、25)下经过驯化,鳃Na+/K+-ATP酶活力显著高于对照组鳃Na+/K+-ATP酶活力(P<0.05),其活力是对照组的2~2.5倍。驯化过程中,3种不同盐度阶段下鳃Na+/K+-ATP酶活力首先表现为下降,随着驯化时间的延长,活力逐渐增加,最后下降并趋于平稳。血清渗透压也随盐度的增加而上升,盐度10时最高,达到(328.77±26.78)mmol.kg-1,此后逐渐下降并稳定在290mmol.kg-1左右,略高于淡水中血清渗透压。不同盐度下,血清渗透压和鳃Na+/K+-ATP酶活力的变化趋势相同。3种不同盐度下史氏鲟血清K+浓度平均值保持在3.00~3.30mmol.L-1之间,与对照组相比无显著差异(P>0.05)。3种盐度下血清Na+和Cl-浓度变化趋势基本一致,随着盐度的增高而增高,盐度20时达到最高。盐度20以下血清Na+和Cl-含量没有显著差异(P>0.05)。史氏鲟血清渗透压调节可以分为3个阶段:一是应激反应阶段,主要表现为鳃Na+/K+-ATP酶活力受到抑制,陡然下降;二是主动调节阶段,鳃Na+/K+-ATP酶被重新激活,且活力逐渐上升;三是适应阶段,鳃Na+/K+-ATP酶趋于平稳。

The activity of Na^＋/K^＋-ATPase in branchia/epithelium, concentration of ions （Na^＋ ,K^＋ ,Cl^- ） and osmolarity in serum of Acipenser schrenckii, during salinity acclimation, were measured and analyzed in this paper, and the osmotic regulation process was discussed. The activity of Na^＋/K^＋ -ATPase in different salinities （10,20,25） was significantly higher than that in control group, which increased by 2 or 2.5 times. Na^＋/K^＋ -ATPase activities under different salinities decreased in the beginning, and increased with the acclimated time elapsing, finally decreased again and tended to be stable. Osmolarity in serum was elevated with the rising salinities. The highest value was （ 328.77 ± 26.78） mmol· kg^-1 in salinity 10. Hereafter, the osmolarity decreased gradually and kept in about 290 mmol· kg^-1. The value was a little higher than that in control group. In all acclimated salinities, the changes on activities of Na^＋/K^＋ -ATPase and serum osmolarity showed the same trend. The concentration of K^＋ in 3 different salinities was firing, but the difference was not significant（ P 〉 0.05） than that in control. The average of K^＋ concentration kept between 3.0 and 3.20 mmol·L^-1 . The trend of Na^＋ and Cl^- concentration changes in serum was similar. The concentrations of Na^＋ and Cl^- were elevated under salinity 10, but the difference was not significant （ P 〉 0.05） than control. The concentration of Na^＋ , Cl^- in serum under 20 and 25 salinities were not significantly different. The osmotic regulation might be divided into 3 phases by analyzing the data in this paper. One is the stress. The obvious symptom is the decrease of Na^＋/K^＋ -ATPase activities. The second phase is active regulation, which is characterized by that the Na^＋/K^＋ -ATPase is activated and its activity is elevated. The last phase is the adaptation. In this phase, the Na^＋/K^＋ -ATPase activities decrease again and are inclined to be stable.