Tissue distribution and neurotoxic effects of domoic acid in a prominent vector species, the northern anchovy Engraulis mordax
Tissue distribution and neurotoxic effects of domoic acid in a prominent vector species, the northern anchovy Engraulis mordax
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DOI：
10.1007/s002270000509
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发表时间：
2001-04-01
期刊：
影响因子：
2.4
通讯作者：
Silver, MW
中科院分区：
文献类型：
--
作者：
Lefebvre, KA;Dovel, SL;Silver, MW
食鱼北方红藻是藻毒素软骨藻酸（DA）向高营养级生物（包括食鱼海鸟和哺乳动物）传播的主要媒介。虽然有大量的数据报告DA诱导的兴奋性毒性症状，在高等脊椎动物，迄今为止，还没有报道的证据，神经毒性作用，在较低的脊椎动物载体，如鱼类。为了解释这种明显缺乏毒性，有人建议，DA可能不会到达大脑中的多巴胺和/或鱼是不敏感的神经DA。在本研究中，体腔内（IC）注射DA，剂量范围从1至14 μ g DA g-1总鱼重，导致严重的神经毒性症状，如旋转，定向障碍，无法上学，和死亡，表明多巴胺在神经学上是易感的，并且DA穿过鱼的血脑屏障。在83个月内通过IC注射DA测定3.2 μ g DA g（-1）总体重的ED 50。小鼠、大鼠和猴子的可比腹腔注射研究报告了在3.2 μ g DA g（-1）纯剂量下相似的DA诱导的神经毒性症状，表明多巴胺和哺乳动物之间相似的神经敏感性和毒性机制。DA组织分布测量新鲜收集的现场暴露的大鼠和口服灌胃大鼠表明，DA从胃肠道吸收确实发生。在哺乳动物内脏中测得的DA水平高达1，175 μ g（-1），而肌肉和脑组织的DA水平低3个数量级，表明低但可测量的DA摄取。需要进一步的证据来证实，在野外活动期间，摄入足以引起腹泻症状。我们的工作提供了鱼类神经毒性症状的第一个证据，并表明在有毒硅藻水华期间，多巴胺可能会影响鱼类。如果发生足够的吸收，DA诱导的神经毒性症状和死亡率可能使鱼类更容易被捕食，从而选择转移的最高毒素水平，以及提供一个可能的途径DA转移到底栖生物群落。
The planktivorous northern anchovy is a prominent vector of the phycotoxin domoic acid (DA) to organisms at higher trophic levels, including fish-eating seabirds and mammals. Although there are abundant data reporting DA-induced excitotoxic symptoms in higher vertebrates, to date there has been no reported evidence of neurotoxic effects in lower vertebrate vectors such as fish. To explain this apparent lack of toxicity, it has been suggested that DA may not reach the brain in anchovies and/or that fish are not as sensitive neurologically to DA. In the present study, intracoelomic (IC) injection of DA, at doses ranging from 1 to 14 mug DA g-1 total fish weight, resulted in severe neurotoxic symptoms such as spinning, disorientation, inability to school, and mortality, indicating that anchovies are neurologically susceptible and that DA crosses the blood-brain barrier in fish. An ED50 Of 3.2 mug DA g(-1) total body weight was determined via IC injection of DA in 83 anchovies. Comparable intraperitoneal injection studies with mice, rats, and monkeys report similar DA-induced neurotoxic symptoms at doses neat 3.2 mug DA g(-1), suggesting a similar neurologic sensitivity and mechanism of toxicity between anchovies and mammals. DA tissue distribution measurements from freshly collected field-exposed anchovies and orally gavaged anchovies indicate that DA uptake from the gastrointestinal tract does occur. Levels as high as 1,175 mug DA g(-1) were measured in anchovy viscera, while muscle and brain tissue DA levels were 3 orders of magnitude lower, indicating low but measurable DA uptake. Further evidence is needed to confirm that uptake is sufficient during field events to induce symptoms in anchovies. Our work provides the first reported evidence of neurotoxic symptoms in fish and suggests that anchovies may be affected by DA during toxic diatom blooms. If sufficient uptake occurs, DA-induced neurotoxic symptoms and mortality may make fish easier prey targets, thereby selecting for the highest toxin levels transferred, as well as providing a possible pathway for the transfer of DA to benthic communities.