Environmental Physiology Laboratory, Department of Earth, Environment and Life Sciences, University of Genoa, Genoa, Italy.
Laboratoire de Biologie du Developpement de Villefranche-sur-mer, Institut de la mer, Sorbonne Université, CNRS, Villefranche-sur-mer, France.
Front Endocrinol (Lausanne). 2022 Feb 25;13:792589. doi: 10.3389/fendo.2022.792589. eCollection 2022.
Contaminants of Emerging Concerns (CECs) are defined as chemicals not commonly monitored in aquatic ecosystems, but with the potential to cause adverse effects on biota. CECs include Endocrine Disrupting Chemicals (EDCs) and Neuro-Endocrine disruptors (NEDs) of vertebrates. However, most invertebrates only rely on neuroendocrine systems to maintain homeostatic processes. Although conserved neuroendocrine components have been characterized in ecologically relevant groups, limited knowledge on invertebrate neuroendocrinology makes it difficult to define EDCs and NEDs in most species. The monoamine serotonin (5-hydroxytryptamine, 5-HT) acts both as a neurotransmitter and as a peripheral hormone in mammals. In molluscs, 5-HT is involved in multiple physiological roles and molecular components of the serotonergic system have been identified. This review is focused on the effects of CECs on the serotonergic system of bivalve molluscs. Bivalves are widespread in all aquatic environments, estuarine and coastal areas in particular, where they are exposed to a variety of chemicals. In bivalves, 5-HT is involved in gametogenesis and spawning, oocyte maturation and sperm motility, regulates heart function, gill ciliary beating, mantle/siphon function, the ''catch'' state of smooth muscle and immune responses. Components of 5-HT transduction (receptors and signaling pathways) are being identified in several bivalve species. Different CECs have been shown to affect bivalve serotonergic system. This particularly applies to antidepressants, among the most commonly detected human pharmaceuticals in the aquatic environment. In particular, selective serotonin reuptake inhibitors (SSRIs) are frequently detected in seawater and in bivalve tissues. Information available on the effects and mechanisms of action of SSRIs on the serotonergic system of adult bivalves is summarized. Data are also reported on the effects of CECs on development of neuroendocrine pathways of early larval stages, in particular on the effects of model EDCs in the marine mussel . Overall, available data point at the serotonergic system as a sensitive target for neuroendocrine disruption in bivalves. The results contribute drawing Adverse Outcome Pathways (AOPs) for model EDCs and SSRIs in larvae and adults. However, basic research on neuroendocrine signaling is still needed to evaluate the potential impact of neuroendocrine disruptors in key invertebrate groups of aquatic ecosystems.
新兴关注污染物（CECs）被定义为在水生生态系统中通常不进行监测但有可能对生物群产生不利影响的化学物质。CECs 包括内分泌干扰物（EDCs）和脊椎动物的神经内分泌干扰物（NEDs）。然而，大多数无脊椎动物仅依靠神经内分泌系统来维持体内平衡过程。尽管在具有生态相关性的群体中已经描述了保守的神经内分泌成分，但对无脊椎动物神经内分泌学的了解有限，使得很难在大多数物种中定义 EDCs 和 NEDs。单胺 5-羟色胺（5-羟色胺，5-HT）在哺乳动物中既作为神经递质又作为外周激素发挥作用。在软体动物中，5-HT 参与多种生理作用，并且已经鉴定出 5-羟色胺能系统的分子成分。本综述重点介绍了 CECs 对双壳类软体动物的 5-羟色胺能系统的影响。双壳类动物广泛存在于所有水生环境中，特别是在河口和沿海地区，它们会接触到各种化学物质。在双壳类动物中，5-HT 参与配子发生和产卵、卵母细胞成熟和精子活力、调节心脏功能、鳃纤毛运动、套膜/水管功能、平滑肌的“捕获”状态和免疫反应。几种双壳类动物中正在鉴定 5-HT 转导的成分（受体和信号通路）。已经表明，不同的 CECs 会影响双壳类动物的 5-羟色胺能系统。这尤其适用于抗抑郁药，它们是水生环境中最常检测到的人类药物之一。特别是，选择性 5-羟色胺再摄取抑制剂（SSRIs）经常在海水中和双壳类动物组织中被检测到。总结了有关 SSRIs 对成年双壳类动物 5-羟色胺能系统的作用和作用机制的信息。还报告了 CECs 对早期幼虫神经内分泌途径发育的影响，特别是模型 EDCs 在海洋贻贝中的影响。总的来说，现有数据表明 5-羟色胺能系统是双壳类动物神经内分泌干扰的敏感靶点。该结果有助于为幼虫和成虫中的模型 EDC 和 SSRIs 绘制不良结局途径（AOPs）。然而，仍然需要对神经内分泌信号进行基础研究，以评估神经内分泌干扰物对水生生态系统关键无脊椎动物群体的潜在影响。
