Department of Physiology
Physiology
Physiology, Tarbiat Modares University, Tehran, Iran
The Inhibitory effect of electrical low-frequency stimulation (LFS) on neuronal excitability and seizure occurrence has been indicated in experimental models, but the precise mechanism has not established. This investigation was intended to figure out the role of α1 and α2 adrenergic receptors in LFS' inhibitory effect on neuronal excitability. Epileptiform activity induced in an in vitro rat hippocampal slice preparation by high K+ ACSF and LFS (900 square wave pulses at 1 Hz,) was administered at the beginning of epileptiform activity to the Schaffer collaterals. In CA1 pyramidal neurons, the electrophysiological properties were measured at the baseline, before high K+ ACSF washout, and at 15 min after high K+ ACSF washout using whole-c
Temporal lobe epilepsy (TLE) is the most common form of focal epilepsy. TLE is characterized by recur‑rent, spontaneous seizures that originate from the temporal lobe (Falconer et al., 1964). The main thera‑peutic intervention for epileptic patients is antiepilep‑tic drugs, but 20–30% of epileptic patients are drug re‑sistant (Schmidt and Schachter, 2014). Therefore, more research has been dedicated to finding new therapies for epilepsy.Over the last decade, deep brain stimulation has been suggested as a treatment for patients with drug‑resistant epilepsy and patients who are not sur‑gical resection candidates (Jobst et al., 2010). Low fre‑quency stimulation (LFS), in the range of 0.5 to 5 Hz, has been shown to suppress seiz
Herein proteomic profiling of the rat hippocampus from the kindling and pilocarpine models of epilepsy was performed to achieve new potential targets for treating epileptic seizures. A total of 144 differently expressed proteins in both left and right hippocampi by two-dimensional electrophoresis coupled to matrix-assisted laser desorption-mass spectrometry were identified across the rat models of epilepsy. Based on network analysis, the majority of differentially expressed proteins were associated with Ca 2+ homeostasis. Changes in ADP-ribosyl cyclase (ADPRC), lysophosphatidic acid receptor 3 (LPAR3), calreticulin, ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1), synaptosomal nerve-associated protein 25 (SNAP 25) and transgelin 3 protein
The mechanisms involved in the anti-seizure effects of low-frequency stimulation (LFS) have not been completely determined. However, Gi-protein-coupled receptors, including D2-like receptors, may have a role in mediating these effects. In the present study, the role of D2-like receptors in LFS’ anti-seizure action was investigated. Rats were kindled with semi-rapid (6 stimulations per day), electrical stimulation of the hippocampal CA1 area. In LFS-treated groups, subjects received four trials of LFS at 5 min, 6 h, 24 h, and 30 h following the last kindling stimulation. Each LFS set occurred at 5 minute intervals, and consisted of 4 trains. Each train contained 200, 0/1 ms long, monophasic square wave pulses at 1 Hz. Haloperidol (D2-like
Objective (s):Seizure detection during online recording of electrophysiological parameters is very important in epileptic patients. In the present study, online analysis of field potential recordings was used for detecting spontaneous seizures in epileptic animals.Materials and Methods:Epilepsy was induced in rats by pilocarpine injection. During the chronic period of the pilocarpine model, local field potential (LFP) recording was run for at least 24 hr. At the same time, video monitoring of the animals was done to determine the real time of seizure occurrence. Both power and sample entropy of LFP were used for online analysis.Results:Obtained results showed that changes in LFP power are a better index for seizure detection. In addition, w
Objective:Sepsis is a leading cause of mortality and morbidity in infants. Although the measures of autonomic dysfunction (eg, reduced heart rate variability) predict mortality in sepsis, the mechanism of sepsis-induced autonomic dysfunction has remained elusive. The nucleus of the solitary tract (NTS) is a vital structure for the integrated autonomic response to physiological challenges. In the present study we hypothesized that sepsis alters the excitability of NTS neurons in a rat model of neonatal sepsis (14-day-old rats).Methods and Results:Sepsis was induced by intraperitoneal injection of cecal slurry (CS) in rat neonates. The presence of autonomic dysfunction was confirmed by observing a significant reduction in both short-term and
Adrenergic receptors have an important role in neural excitability and synaptic plasticity. Despite a lot of studies on these receptors, their exact role in brain disorders accompanied with hyperexcitability has not been determined. There are also controversies on their role in synaptic plasticity. In this review article, the important studies done in this regard have been reviewed to achieve a good summary of the effects of these receptors on neuronal excitability and synaptic plasticity. Despite the controversial results that have been reported in previous studies, it seems that alpha-1 and alpha-2 receptors decrease the neuronal excitability during seizure. Alpha 1A receptors, by acting on inhibitory interaneurons and increasing the GABA
Objective (s):Cell therapy has provided clinical applications to the treatment of motor neuron diseases. The current obstacle in stem cell therapy is to direct differentiation of stem cells into neurons in the neurodegenerative disorders. Biomaterial scaffolds can improve cell differentiation and are widely used in translational medicine and tissue engineering. The aim of this study was to compare the efficiency of two-dimensional with a three-dimensional culture system in their ability to generate functional motor neuron-like cells from adipose-derived stem cells.Materials and Methods:We compared motor neuron-like cells derived from rat adipose tissue in differentiation, adhesion, proliferation, and functional properties on two-dimensional
Glial activation is a common pathological process of the central nervous system (CNS) in disorders such as Alzheimer's disease (AD). Several approaches have been used to reduce the number of activated astrocytes and microglia in damaged areas. In recent years, various kinds of fully differentiated cells have been successfully reprogrammed to a desired type of cell in lesion areas. Interestingly, internal glial cells, including astrocytes and NG2 positive cells, were efficiently converted to neuroblasts and neurons by overexpression of some transcription factors (TFs) or microRNAs (miRNAs). Notably, some specific subtypes of neurons have been achieved by in vivo reprogramming and the resulting neurons were successfully integrated into local
Epilepsy is the most common neurological disease with no definitive method in treatment. Notably, the main way to treat and control epileptic seizures is drug therapy. However, about 20-30% of patients with epilepsy are drug resistant and require other therapeutic manners. Deep brain stimulation is a new therapeutic strategy for these patients. Conspicuously, there are no clear answers for basic questions such as which brain area is a suitable target for stimulation, which pattern of stimulation exerts the best therapeutic effects and what is the probable mechanism of anticonvulsant effect of deep brain stimulation? Using laboratory models of epilepsy and seizure, it has been shown that low frequency electrical stimulation (LFS) is an effec
This paper reports on the design, development, and test of a multi-channel wireless micro-electrocorticography (?ECoG) system. The system consists of a semi-implantable, ultra-compact recording unit and an external unit, interfaced through a 2.4 GHz radio frequency data telemetry link with 2 Mbps (partially used) data transfer rate. Encased in a 3D-printed 2.9 cm? 2.9 cm? 2.5 cm cubic package, the semi-implantable recording unit consists of a microelectrode array, a vertically-stacked PCB platform containing off-the-shelf components, and commercially-available small-size 3.7-V, 50 mAh lithium-ion batteries. Two versions of microelectrode array were developed for the recording unit: a rigid 4? 2 microelectrode array, and a flexible 12? 6 mic
Methods:The rats were implanted with a recording electrode in stratum radiatum and stimulating electrodes in Schaffer collaterals of the CA1 region in the dorsal hippocampus of the right hemisphere. Following the recovery period of at least 10 days, field potentials were recorded in freely moving animals before and after training them in Barnes maze as a hippocampal-dependent spatial learning and memory test. The slope of extracellular field Excitatory Postsynaptic Potentials (fEPSPs) was measured before and after the Barnes maze test.Results:The results showed that the fEPSP slope did not change after learning and memory in the Barnes maze test, and this spatial learning did not result in a change in synaptic potentiation in the CA1 region
Low frequency stimulation (LFS) has anticonvulsant effect and may restore the ability of long-term potentiation (LTP) to the epileptic brain. The mechanisms of LFS have not been completely determined. Here, we showed that LTP induction was impaired following in vitro epileptiform activity (EA) in hippocampal slices, but application of LFS prevented this impairment. Then, we investigated the involvement of α-adrenergic receptors in this effect of LFS. EA was induced by increasing the extracellular K+ concentration to 12 mM and EPSPs were recorded from CA1 neurons in whole cell configuration. EA increased EPSP amplitude from 6.9 ? 0.7 mV to 9.6 ? 0.6 mV. For LTP induction, the Schaffer collaterals were stimulated by high freque
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