铜、镉对鮸鱼幼鱼鳃丝Na^＋ -K^＋ -ATPase和肝脏SOD酶活性的影响

以鮸鱼（Miichthysmiiuy）幼鱼为研究对象,研究了Cu^2＋和Cd2＋对鮸鱼幼鱼鳃丝Na^＋-K^＋-ATPase和肝脏SOD酶活性的影响。以6个Cu^2＋浓度（0.01mg/L、0.05mg/L、0.1mg/L、0.2mg/L、0.4mg/L和0.8mg/L）和6个Cd^2＋浓度（0.005mg/L、0.025mg/L、0.05mg/L、0.1mg/L、0.2mg/L、0.4mg/L）对鮸鱼幼鱼进行8d染毒。结果表明,Cu^2＋和Cd^2＋各处理组鱼鳃丝Na^＋-K^＋-ATPase活力随取样时间的变化显著（P〈0.05）,且呈峰值变化,在1d时达到最大值,然后缓慢下降,最后各处理组酶活力趋于稳定。两种重金属离子对鮸鱼鳃丝Na^＋-K^＋-ATPase活力的影响在同一取样时间各处理组间的差异也显著（P〈0.05）,其影响程度与重金属的浓度呈负相关,且Cd2＋浓度为0.4mg/L时,在第8天酶活力与对照组的差异不显著（P〉0.05）。Cu^2＋和Cd2＋在1～8d对鮸鱼鳃丝Na^＋-K^＋-ATPase活力的诱导率表现为Cu^2＋〉Cd^2＋。低浓度组Cu^2＋和Cd^2＋曝露时,鮸鱼肝组织中SOD活性变化在短时间内不明显（P〉0.05）,但随着时间的延长,SOD活性提高,与对照组差异显著（P〈0.05）,导致“毒物兴奋效应”。高浓度Cu^2＋和Cd^2＋曝露时,随着时间的延长和浓度的增强,肝组织SOD的活力抑制越明显（P〈0.05）。

Effects of Cu2+ and Cd2+ on Na+-K+-ATPase activity of gills and superoxide dismutase activity of liver in Miichthys miiuy

The present paper intends to introduce the experimental results of ours on the effects of Cu2+ and Cd2+ on Na+-K+-ATPase activity of gills and superoxid dismutase activity of the liver in Miichthys miiuy.In our experiments,we have adopted early cultivated juvenile Miichthys miiuy with their average weight between 10.0-11.2 g and average length of about 9.5-10.0 cm.As a rule,it took usually 8 days to domesticate the fish before the experiments began.The results of our experiments indicate that Cu2+(0.01 mg/L,0.05 mg/L,0.1 mg/L,0.2 mg/L,0.4 mg/L and 0.8 mg/L)and Cd2+(0.005 mg/L,0.025 mg/L,0.05 mg/L,0.1 mg/L,0.2 mg/L,0.4 mg/L)may produce significant effect(P<0.05)on the Na+-K+-ATPase activities with the changing curve of the Na+-K+-ATPase activity reaching its marked peak value on the first day.At the same time,the Na+-K+-ATPase activity in each group of the two kinds of metal ions also proved to be significant(P<0.05),though the relation of the activity with their concentration seems negative in nature.Meanwhile,the inductive ration of the two heavy metal ions on the Na+-K+-ATPase activities prove to be Cu2+>Cd2+.Thus,the results of our experiments indicate that the activities of SOD in their liver have not brought any obvious changes at low Cu2+ and Cd2+ concentrations in a short time.However,the activities can be promoted with prolonging the exposure time,which can probably be expected to come about as a result of the so-called "toxic excitement effect".