title: Exposure to extremely low frequency electromagnetic fields alters the calcium dynamics of cultured entorhinal cortex neurons.
abstract: Previous studies have revealed that extremely low frequency electromagnetic field (ELF-EMF) exposure affects neuronal dendritic spine density and NMDAR and AMPAR subunit expressions in the entorhinal cortex (EC). Although calcium signaling has a critical role in control of EC neuronal functions, however, it is still unclear whether the ELF-EMF exposure affects the EC neuronal calcium homeostasis. In the present study, using whole-cell recording and calcium imaging, we record the whole-cell inward currents that contain the voltage-gated calcium currents and show that ELF-EMF (50Hz, 1mT or 3mT, lasting 24h) exposure does not influence these currents. Next, we specifically isolate the high-voltage activated (HVA) and low-voltage activated (LVA) calcium channels-induced currents. Similarly, the activation and inactivation characteristics of these membrane calcium channels are also not influenced by ELF-EMF. Importantly, ELF-EMF exposure reduces the maximum amplitude of the high-K(+)-evoked calcium elevation in EC neurons, which is abolished by thapsigargin, a Ca(2+) ATPase inhibitor, to empty the intracellular calcium stores of EC neurons. Together, these findings indicate that ELF-EMF exposure specifically influences the intracellular calcium dynamics of cultural EC neurons via a calcium channel-independent mechanism.
authors.affiliation: Department of Physiology, Third Military Medical University, Chongqing 400038, PR China.
authors.forename: Fen-Lan
authors.initials: FL
authors.lastname: Luo
authors.affiliation: Department of Physiology, Third Military Medical University, Chongqing 400038, PR China.
authors.forename: Nian
authors.initials: N
authors.lastname: Yang
authors.affiliation: Department of Physiology, Third Military Medical University, Chongqing 400038, PR China.
authors.forename: Chao
authors.initials: C
authors.lastname: He
authors.affiliation: Department of Histology and Embryology, Third Military Medical University, Chongqing 400038, PR China.
authors.forename: Hong-Li
authors.initials: HL
authors.lastname: Li
authors.affiliation: Department of Physiology, Third Military Medical University, Chongqing 400038, PR China.
authors.forename: Chao
authors.initials: C
authors.lastname: Li
authors.affiliation: Department of Physiology, Third Military Medical University, Chongqing 400038, PR China.
authors.forename: Fang
authors.initials: F
authors.lastname: Chen
authors.affiliation: Department of Physiology, Third Military Medical University, Chongqing 400038, PR China.
authors.forename: Jia-Xiang
authors.initials: JX
authors.lastname: Xiong
authors.affiliation: Department of Physiology, Third Military Medical University, Chongqing 400038, PR China. Electronic address: zhianhu@aliyun.com.
authors.forename: Zhi-An
authors.initials: ZA
authors.lastname: Hu
authors.affiliation: Department of Physiology, Third Military Medical University, Chongqing 400038, PR China. Electronic address: zhangjun.cc@gmail.com.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D004574:Electromagnetic Fields / Q000009:adverse effects*; D018728:Entorhinal Cortex / Q000166:cytology* / Q000528:radiation effects; D009474:Neurons / Q000378:metabolism* / Q000528:radiation effects; D018408:Patch-Clamp Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D015220:Calcium Channels; D002118:Calcium
keywords: Calcium channel; Calcium dynamics; Entorhinal cortex; Extremely low frequency electromagnetic fields