Laboratory of Ecotoxicology, Faculty of Environmental Science, University of Castilla-La Mancha, Avda. Carlos III s/n, 45071, Toledo, Spain; Department of Animal Ecophysiology, Faculty of Sciences, University of Chile, Chile.
Comp Biochem Physiol C Toxicol Pharmacol. 2010 Apr;151(3):351-9. doi: 10.1016/j.cbpc.2009.12.008. Epub 2010 Jan 5.
Exposure and effect assessment of organophosphate (OP) pesticides generally involves the use of cholinesterase (ChE) inhibition. In earthworm, this enzyme activity is often measured in homogenates from the whole organism. Here we examine the tissue-specific response of ChE and carboxylesterase (CE) activities in Lumbricus terrestris experimentally exposed to chlorpyrifos-spiked field soils. Esterases were measured in different gut segments and in the seminal vesicles of earthworms following acute exposure (2 d) to the OP and during 35d of a recovery period. We found that inhibition of both esterase activities was dependent on the tissue. Cholinesterase activity decreased in the pharynx, crop, foregut and seminal vesicles in a concentration-dependent way, whereas CE activity (4-nitrophenyl valerate) was strongly inhibited in these tissues. Gizzard CE activity was not inhibited by the OP, even an increase of enzyme activity was evident during the recovery period. These results suggest that both esterases should be determined jointly in selected tissues of earthworms. Moreover, the high levels of gut CE activity and its inhibition and recovery dynamic following OP exposure suggest that this esterase could play an important role as an enzymatic barrier against OP uptake from the ingested contaminated soil.
有机磷（OP）农药的暴露和效应评估通常涉及使用胆碱酯酶（ChE）抑制。在蚯蚓中，通常在整个生物体的匀浆中测量这种酶活性。在这里，我们研究了实验暴露于毒死蜱污染田间土壤的赤子爱胜蚓中 ChE 和羧酸酯酶（CE）活性的组织特异性反应。在急性暴露（2 天）后以及在 35 天的恢复期内，在蚯蚓的不同肠道段和精囊内测量酯酶。我们发现，两种酯酶活性的抑制均取决于组织。ChE 活性在咽部，嗉囊，前肠和精囊内呈浓度依赖性降低，而 CE 活性（4-硝基苯戊酸酯）在这些组织中受到强烈抑制。OP 对砂囊 CE 活性没有抑制作用，即使在恢复期内，酶活性也明显增加。这些结果表明，应该在蚯蚓的选定组织中联合测定这两种酯酶。此外，肠道 CE 活性及其在 OP 暴露后的抑制和恢复动态水平很高，表明该酯酶可能在防止从摄入的受污染土壤中摄取 OP 方面发挥重要的酶屏障作用。
