Early exposure to radiofrequency electromagnetic fields at 1850 MHz affects auditory circuits in early postnatal mice

Abstract

In the present study, we measured the spontaneous post synaptic currents (sPSCs) at the post synaptic principle cells of the medial nucleus of the trapezoid body (MNTB) in early postnatal mice after exposure to 1850 MHz radiofrequency electromagnetic fields (RF-EMF). sPSC frequencies and amplitudes were significantly increased in the RF-EMF exposed group. Moreover, the number of synaptic vesicles in the calyx of Held was significantly increased in presynaptic nerve terminals. Following RF-EMF exposure, the number of docking synaptic vesicles in the active zone increased, thereby expanding the total length of the presynaptic active zone in the calyx of Held. These data suggest that the increased sPSCs are a result of greater synaptic vesicle release from presynaptic nerves. However, we found no morphological changes in the inner hair cell ribbon synapses. Further, there were no significant changes in the hearing threshold of the auditory brainstem response at postnatal day 15. Our results indicate that exposure to RF-EMF at an early postnatal stage might directly affect brainstem auditory circuits, but it does not seem to alter general sound perception.

Trafficking of synaptic vesicles is changed at the hypothalamus by exposure to an 835 MHz radiofrequency electromagnetic field

“…3). These data are consistent with previous studies with regards to the number of SVs but is inconsistent with previous studies in terms of the size of the SVs (Kim et al 2017a(Kim et al , 2019a(Kim et al , 2019b. It has been previously reported that overexpression of synapsin Ia leads to a decrease in the size of SVs and active zones in the rat calyx of Held, thus mediating SV distribu- tion within the presynaptic terminal (Vasileva et al 2013).…”

“…The number of SVs was significantly decreased but the size of the SVs was significantly increased in cortical neurons and dopaminergic neurons of the striatum after RF-EMF exposure (Kim et al 2019b). However, the number of SVs in MNTB neurons in the auditory system was increased by RF-EMF exposure (Kim et al 2019a). These data indicated that different regions of the brain are differentially respondent to RF-EMF exposure.…”

“…The best-known function of synapsin proteins is to regulate synaptic transmission by controlling the storage and mobilization of SVs (Vasileva et al 2012). We previously reported that RF-EMF exposure could lead to alteration in the number and size of SVs located in the cortex (Kim et al 2017a), striatum (Kim et al 2019b), and medial nucleus of the trapezoid body (MNTB) neurons in the auditory system (Kim et al 2019a). The number of SVs was significantly decreased but the size of the SVs was significantly increased in cortical neurons and dopaminergic neurons of the striatum after RF-EMF exposure (Kim et al 2019b).…”

“…We previously reported that the number and size of the synaptic vesicles at presynaptic nerve terminals may be changed in the auditory brainstem, cerebral cortex and striatum of mice after exposure to RF-EMF (Kim et al 2017a(Kim et al , 2019a(Kim et al , 2019b. These studies also suggested that alterations in SV trafficking are caused by changes in the expression levels of synapsins and calcium ion channels (Evergren et al 2007;Cesca et al 2010) .…”

Does mobile phone use of women during pregnancy cause hearing problems in infants? Preliminary observation

“…Ön gözlem tion, neurotransmitter release, lead to alterations in the regulation of the cell cycle, and change intracellular and some molecular pathways, and cause alterations in the central nervous system. [1] The most important groups in terms of health problems that electromagnetic field (EMF) exposure can affect are pregnant women and children. In a workshop organized by the World Health Organization in Istanbul, Turkey, in 2004, the sensitivity of children to EMFs was discussed and it was emphasized that studies on this subject should be increased.…”