Effects of environmental pollutants on calcium release and uptake by rat cortical microsomes

Hanna M. Dusza, Peter H. Cenijn, Jorke H. Kamstra, Remco H.S. Westerink, Pim E.G. Leonards, Timo Hamers*

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


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.

Original languageEnglish
Pages (from-to)266-277
Number of pages12
Early online date26 Jul 2018
Publication statusPublished - Dec 2018


This study was performed within the EU FP7 funded project DENAMIC (DEvelopmental Neurotoxicity Assessment of MIxtures in Children; Contract No. 282957). The authors gratefully acknowledge Vesna Lavtizar (University of Nova Gorica, Slovenia) for providing transformation products TP1 and TP2 of chlorantraniliprole, and Sicco Brandsma and Freek Ariese (Vrije Universiteit Amsterdam) for performing the alpha-cypermethrin analyses and for hosting the fluorescence measurements on the Cary Eclipse Fluorescence Spectrophotometer, respectively. Post-mortem cortex tissue was obtained from Wistar rats sacrificed for other research projects of Vrije Universiteit Amsterdam in accordance with the European Council Directive (86/609/EEC) by permission of the Animal Research Law of The Netherlands. Appendix A

FundersFunder number
European Council86/609/EEC
University of Nova Gorica
Vesna Lavtizar
Seventh Framework Programme282957


    • Calcium homeostasis
    • Environmental pollutants
    • IP receptor
    • Microsomes
    • Neurotoxicity
    • Ryanodine receptor
    • SERCA


    Dive into the research topics of 'Effects of environmental pollutants on calcium release and uptake by rat cortical microsomes'. Together they form a unique fingerprint.

    Cite this