Dysregulation of neuronal intracellular Ca²⁺ homeostasis can play a crucial role in many neurotoxic effects, including impaired brain development and behavioral dysfunctions. This study examined 40 suspected neurotoxicants from different chemical classes for their capacity to alter Ca²⁺ release and uptake from rat cortical microsomes. First, ten suspected neurotoxicants have been tested using a well-established cuvette-based Ca²⁺ flux assay. Five out of ten compounds (TOCP, endosulfan, PCB-95, chlorpyrifos and BDE-49) showed a significant, concentration-dependent alteration of Ca²⁺ release and uptake in adult rat cortical microsomes. The original cuvette assay was downscaled and customized to a fast, higher throughput microplate method and the 40 suspected neurotoxicants were screened for their effects on intracellular Ca²⁺homeostasis. In decreasing order of potency, the 15 test compounds that showed the strongest alteration of Ca²⁺ levels in adult rat microsomes were TOCP, endosulfan, BDE-49, 6-OH-BDE-47, PCB-95, permethrin, alpha-cypermethrin, chlorpyrifos, bioallethrin, cypermethrin, RDP, DEHP, DBP, BDE-47, and PFOS. Results from co-exposure experiments with selective inhibitors suggested that for some compounds Ca²⁺ releasing effects could be attributed to RyR activation (PFOS, DBP, and DEHP) or to SERCA inhibition (a potential novel mechanism of action for all four tested pyrethroid insecticides). The effects of the two most potent compounds, endosulfan and TOCP, were not blocked by any of the inhibitors tested, indicating other possible mechanism of action. For all other potent test compounds, a combined effect on RyR, IP₃R, and/or SERCA has been observed. PFOS and 6-OH-BDE-47 caused increased Ca²⁺ release from adult but not from neonatal rat brain microsomes, indicating age-dependent difference in susceptibility to these test compounds. The current study suggests that the neurotoxic potential of compounds belonging to different chemical classes could partly be attributed to the effects on intracellular Ca²⁺ release and uptake. Although further validation is required, the downscaled method developed in this study presents technical advance that could be used for the future screening of suspected intracellular Ca²⁺ disruptors.

神经元细胞内Ca ²⁺稳态的失调可以在许多神经毒性作用中发挥关键作用，包括损害大脑发育和行为功能障碍。这项研究检查了40种来自不同化学类别的可疑神经毒素，它们具有改变Ca ²⁺释放和从大鼠皮质微粒体吸收的能力。首先，已经使用成熟的基于比色杯的Ca ²⁺通量测定法测试了十种疑似神经毒物。十分之五的化合物（TOCP，硫丹，PCB-95，毒死rif和BDE-49）显示出浓度依赖性的Ca ²⁺显着改变成年大鼠皮质微粒体的释放和摄取。原始比色皿分析仪被缩减规模，并被定制为一种快速，高通量的微孔板方法，并筛选了40种可疑神经毒剂对细胞内Ca ²⁺稳态的影响。在效力递减的顺序中，显示成年大鼠微粒体中Ca ²⁺水平变化最强的15种受试化合物是TOCP，硫丹，BDE-49、6-OH-BDE-47，PCB-95，氯菊酯，α-氯氰菊酯，毒死rif，生物菊酯，氯氰菊酯，RDP，DEHP，DBP，BDE-47和PFOS。选择性抑制剂共同暴露实验的结果表明，对于某些化合物，Ca ²⁺释放作用可能归因于RyR激活（PFOS，DBP和DEHP）或SERCA抑制（对所有四种被测试的拟除虫菊酯杀虫剂潜在的新作用机理）。两种最有效的化合物硫丹和TOCP的作用均未被任何测试的抑制剂所阻断，这表明了其他可能的作用机理。对于所有其他有效的测试化合物，已观察到对RyR，IP ₃ R和/或SERCA的综合作用。PFOS和6-OH-BDE-47引起Ca ²⁺增加从成年动物体内释放而不是从新生大鼠脑微粒体内释放出来，表明这些试验化合物对年龄的敏感性不同。目前的研究表明，属于不同化学类别的化合物的神经毒性潜力可能部分归因于对细胞内Ca ²⁺释放和吸收的影响。尽管需要进一步的验证，但本研究中开发的缩小规模的方法仍可提供技术进步，可用于将来筛选可疑的细胞内Ca ²⁺干扰物。