State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China.
Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao Pilot National Laboratory for Marine Science and Technology, Qingdao 266200, China.
Environ Sci Technol. 2023 Jun 20;57(24):8921-8932. doi: 10.1021/acs.est.3c00707. Epub 2023 Jun 5.
Biological burrowing behavior is an important driver shaping ecosystems that is being threatened by CO-induced ocean acidification; however, the effects of ocean acidification on burrowing behavior and its neurological mechanism remain unclear. This study showed that elevated CO significantly affected the burrowing behaviors of the Manila clam , such as increased foot contraction, burrowing time, and intrabottom movement and decreased burrowing depth. Delving deeper into the mechanism, exposure to elevated CO significantly decreased extracellular pH and increased [HCO]. Moreover, an indicator GABA receptor, a neuroinhibitor for movement, was found to be closely associated with behavioral changes. hybridization confirmed that the GABA receptor was widely distributed in ganglia and foot muscles, and elevated CO significantly increased the mRNA level and GABA concentration. However, the increase in GABA receptor and its ligand did not suppress the foot movement, but rather sent "excitatory" signals for foot contraction. The destabilization of acid-base homeostasis was demonstrated to induce an increase in the reversal potential for GABA receptor and an alteration in GABA receptor function under elevated CO. This study revealed that elevated CO affects the burrowing behavior of Manila clams by altering GABA receptor function from inhibitory to excitatory.
生物钻洞行为是塑造生态系统的重要驱动力，正受到 CO2 引起的海洋酸化的威胁；然而，海洋酸化对钻洞行为及其神经机制的影响仍不清楚。本研究表明，升高的 CO2 显著影响了马尼拉蛤的钻洞行为，如足收缩、钻洞时间、底内移动增加和钻洞深度减少。进一步深入研究其机制发现，暴露于升高的 CO2 显著降低了细胞外 pH 值并增加了[HCO3-]。此外，一种 GABA 受体（运动的神经抑制剂）的指标与行为变化密切相关。杂交实验证实，GABA 受体广泛分布于神经节和足部肌肉中，升高的 CO2 显著增加了其 mRNA 水平和 GABA 浓度。然而，GABA 受体及其配体的增加并没有抑制足部运动，而是为足收缩发出了“兴奋”信号。研究表明，酸碱平衡的不稳定会导致 GABA 受体的反转电位增加，并在升高的 CO2 下改变 GABA 受体的功能，从而导致酸碱平衡不稳定。本研究揭示了升高的 CO2 通过将 GABA 受体的功能从抑制性转变为兴奋性来影响马尼拉蛤的钻洞行为。
