The present study evaluates the consequences of high frequency (25 hz) trans-cranial magnetic stimulation on the expression of glial fibrillary acidic protein (GFAP) in the murine CNS. Trains of transcranial magnetic stimulation (1-30 trains at 25 Hz, 10 s duration) were delivered to mice via 5-cm diameter round coils. The stimulation produced stimulus-locked motor responses but did not elicit behavioral seizures. GFAP mRNA levels were evaluated 12, 24, 36, 48 h, 4 days, and 8 days following stimulation by in situ hybridization. Following multiple 25 Hz trains, there were dramatic increases in the levels of GFAP mRNA in the hippocampal dentate gyrus; more modest increases were observed in the cerebral cortex. The selective increases in GFAP mRNA in the dentate gyrus were similar to those observed following single electroconvulsive seizures (ECS). These results indicate that trans-cranial magnetic stimulation can be used to modulate astroglial gene expression, inducing the first stage of a reactive response that is similar to what occurs following nervous system injury.
"Interestingly, Wang et al.  provided the first evidence that rTMS induces changes in BDNF-TrkB signaling in the rat brain, which are reflected in lymphocytes. Transcription of glial fibrillary acidic protein (GFAP) is increased in astrocytes of the mouse dentate gyrus (the magnitude of this response depends on the number of stimulus trains), suggesting that rTMS induces the first stage of a reactive response that is similar to what occurs following nervous tissue injury . However, the consequences of rTMS on experimental animals after stroke have been poorly investigated. "
[Show abstract][Hide abstract] ABSTRACT: Stroke is a common and disabling global health-care problem, which is the third most common cause of death and one of the main causes of acquired adult disability in many countries. Rehabilitation interventions are a major component of patient care. In the last few years, brain stimulation, mirror therapy, action observation, or mental practice with motor imagery has emerged as interesting options as add-on interventions to standard physical therapies. The neural bases for poststroke recovery rely on the concept of plasticity, namely, the ability of central nervous system cells to modify their structure and function in response to external stimuli. In this review, we will discuss recent noninvasive strategies employed to enhance functional recovery in stroke patients and we will provide an overview of neural plastic events associated with rehabilitation in preclinical models of stroke.
"Direct evidence for astrocytic involvement in the neuromodulatory therapy is limited. Early work in a murine model found that high frequency TMS had a dramatic effect in the upregulation of astroglial gene expression (Fujiki and Steward, 1997) Following multiple high frequency trains (25 Hz), GFAP mRNA levels were significantly increased in the hippocampal dentate gyrus to levels similar to that following electroconvulsive seizures, indicating induction of an astrocytic reactive response (Fujiki and Steward, 1997). Indirectly, the analogous effects to LTD and LTP have important implications for astrocyte involvement, as the important contributions of astrocytes and gliotransmitters to synaptic plasticity have been described in multiple neuronal circuits (Yang et al., 2003; Witcher et al., 2007; Henneberger et al., 2010; Ben Menachem-Zidon et al., 2011; Bonansco et al., 2011; Navarrete et al., 2012). "
[Show abstract][Hide abstract] ABSTRACT: Epilepsy is a common chronic neurologic disorder affecting approximately 1% of the world population. More than one-third of all epilepsy patients have incompletely controlled seizures or debilitating medication side effects in spite of optimal medical management. Medically refractory epilepsy is associated with excess injury and mortality, psychosocial dysfunction, and significant cognitive impairment. Effective treatment options for these patients can be limited. The cellular mechanisms underlying seizure activity are incompletely understood, though we here describe multiple lines of evidence supporting the likely contribution of astroglia to epilepsy, with focus on individual astrocytes and their network functions. Of the emerging therapeutic modalities for epilepsy, one of the most intriguing is the field of neuromodulation. Neuromodulatory treatment, which consists of administering electrical pulses to neural tissue to modulate its activity leading to a beneficial effect, may be an option for these patients. Current modalities consist of vagal nerve stimulation, open and closed-loop stimulation, and transcranial magnetic stimulation. Due to their unique properties, we here present astrocytes as likely important targets for the developing field of neuromodulation in the treatment of epilepsy.
"Some studies indicate that electromagnetic fields modulate the behavior of neural cells in vitro by varying the action potential of neural networks  or growth factor stimulation , others provide assumptions of non-neuronal cellular mechanisms . Up to now there is little knowledge about the cell response of neural networks in the level of gene expression   and signal transduction   caused by MS. The aim of our study was to elucidate the effects of repetitive MS on the gene expression of in vitro cultured murine neural stem cells by applying different stimulation patterns in repeated treatments according to empirical approaches in therapy . "
[Show abstract][Hide abstract] ABSTRACT: Transcranial magnetic stimulation is a non-invasive tool in clinical diagnostics and therapy for physiological and psychological diseases and has an increased application in experimental neurophysiology. Despite this, the mechanisms of magnetic stimulation of the central nervous system remain still unclear. We applied sinus-shaped high frequency magnetic fields in different stimulation patterns and repeated treatments to cell cultures derived from frontal cortex of murine embryos (BALB/cOlaHsd mice) to elucidate the effects of repetitive magnetic stimulation on the gene expression of in vitro cultured neural cells. Gene expression profiling was performed by using qRT-PCR array and single qRT-PCR analyses. Our methodological approach using microelectrode arrays data recording and analysis minimizes variations in transcriptome analysis arising from cell differentiation status and tissue complexity. With 10 significant changes in gene expression out of 171 genes using Alzheimer disease and neurodegeneration related qRT-PCR arrays we demonstrate significant impact of repetitive magnetic stimulation on the mRNA transcript of neural cell cultures. Sixteen candidate genes were analyzed using single qRT-PCR in a replicated statistical design, which provided more precise estimates of differences in expression profiles. We discussed the utility of the experimental methods used for cell culture selection and the changes in gene expression considering physiological aspects.
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