NTPDase and acetylcholinesterase activities in silver catfish, Rhamdia quelen (Quoy & Gaimard, 1824) (Heptapteridae) exposed to interaction of oxygen and ammonia levels

Neotropical Ichthyology

Cíntia Saydelles da Rosa¹  Bernardo Baldisserotto¹  Vania Lúcia Loro¹  Alexssandro G. Becker¹  Luciane Almeri Tabaldi¹  Rosilene Rodrigues Kaizer¹  Luciano de Oliveira Garcia¹  Maria Rosa Chitolina Schetinger¹  Vera Maria Morsch¹ 

[1] Universidade Federal de Santa Maria;

关键词: Fish;    ATP;    ADP;    AChE;   

DOI  :  10.1590/S1679-62252009000400012

来源: DOAJ

【 摘 要 】

The effects of various levels of oxygen saturation and ammonia concentration on NTPDase (ecto-nucleoside triphosphate diphosphohydrolase, E.C. 3.6.1.5) and acetylcholinesterase (AChE, E.C. 3.1.1.7) activities in whole brain of teleost fish (Rhamdia quelen) were investigated. The fish were exposed to one of two different dissolved oxygen levels, including high oxygen (6.5 mg.L-1) or low oxygen (3.5 mg.L-1), and one of two different ammonia levels, including high ammonia (0.1 mg.L-1) or low ammonia (0.03 mg.L-1) levels. The four experimental groups included the following (A) control, or high dissolved oxygen plus low NH3; (B) low dissolved oxygen plus low NH3; (C) high dissolved oxygen plus high NH3; (D) low dissolved oxygen plus high NH3. We found that enzyme activities were altered after 24 h exposure in groups C and D. ATP and ADP hydrolysis in whole brain of fish was enhanced in group D after 24 h exposure by 100% and 119%, respectively, compared to the control group. After 24 h exposure, AChE activity presented an increase of 34% and 39% in groups C and D, respectively, when compared to the control group. These results are consistent with the hypothesis that low oxygen levels increase ammonia toxicity. Moreover, the hypoxic events may increase blood flow by hypoxia increasing NTPDase activity, thus producing adenosine, a potent vasodilator.

【 授权许可】

Unknown