Differential intensity-dependent effects of magnetic stimulation on the longest neurites and shorter dendrites in neuroscreen-1 cells

Abstract

OBJECTIVE Magnetic stimulation (MS) is a potential treatment for neuropsychiatric disorders. This study investigates whether MS-regulated neuronal activity can translate to specific changes in neuronal arborization and thus regulate synaptic activity and function. APPROACH To test our hypotheses, we examined the effects of MS on neurite growth of Neuroscreen-1 (NS-1) cells over pulse frequencies of 1, 5 and 10 Hz at field intensities controlled by machine output (MO). Cells were treated with either 30% or 40% MO and received either maximal or minimal MS-induced current-density. Due to the nature of circular MS coils, the center region of the gridded coverslip (zone 1) received minimal (~5%) electromagnetic current density while the remaining area (zone 2) received maximal (~95%) current density. Plated NS-1 cells were exposed to MS twice per day for 3 days and then evaluated for length and number of neurites and expression of brain-derived neurotrophic factor (BDNF). MAIN RESULTS We show that MS dramatically affects the growth of the longest neurites (axon-like) but does not significantly affect the growth of shorter neurites (dendrite-like). Also, MS-induced changes in the longest neurite growth were most evident in zone 1, but not in zone 2. MS effects were intensity-dependent and were most evident in the bolstering of the longest neurite outgrowth, mainly seen in the 10 Hz MS group. Furthermore, we found that MS-increased BDNF expression and secretion was also frequency-dependent. Taken together, our results show that MS exerts distinct effects when different frequencies and intensities are applied to the neuritic compartments (longest neurite versus shorter dendrite(s)) of NS-1 cells. SIGNIFICANCE These findings support the concept that MS increases BDNF expression and signaling, which sculpts longest neurite arborization and connectivity by which neuronal activity is regulated. Understanding the mechanisms underlying MS is crucial for efficiently incorporating its use into potential therapeutic strategies.

Pulsed EMF stimulation increased BDNF and activated S6 levels in the hippocampus of senescent rats

“…This possibility is especially noticeable in the advanced age in which active physical training has limited applicability. This line of reasoning is corroborated by results published earlier [14], accordingly, the EMF treatment markedly enhanced the growth of longest neurites and simultaneously increased the BNDF expression in Neuroscreen-1 cells in vitro.…”

Astrocytes contribute to the neuronal recovery promoted by high‐frequency repetitive magnetic stimulation in in vitro models of ischemia

“…Synaptic plasticity can also be promoted through morphological changes in neuronal networks, or, in the case of IS, through the prevention of neurite degeneration, being this enhancement of functional connectivity associated with the reorganization of neuronal networks after ischemia (Li et al, 2016). Although the ability of HF-rTMS to increase neurite length and neuronal arborization under non-pathological conditions was already observed (Lin et al, 2015;Ma et al, 2013;Vlachos et al, 2012), our results demonstrate that HF-rMS protects neurites from the ischemia-induced degeneration and reduction of neuronal arborization. To our knowledge, it was the first time that these effects were demonstrated on models of IS.…”