Department of Physiology (2002 - Present)
Physiology
, Tarbiat Modares University,
Physiology
, Tarbiat Modares University,
biology
, ,
Our general goal is to understand the hyper-excitability-induced changes in synaptic transmission and synaptic plasticity. We are particularly interested to know the effect of brain stimulation on modulation of these changes. In addition, finding the mechanisms involved in modulatory effects of brain stimulation on synaptic transmission are of our interest. We have also focused on hyper-excitability induced impairments in learning and memory, and on the probable preventing effect of brain stimulation on these imparements. For induction of hyper-excitability, we use different laboratory techniques for induction of seizure behavior in vivo (e.g. electrical and chemical kindling, electroshock, pilocarpine injection) or in vitro (e.g. high K induced epileptiform activity). These questions are studied by employing a combination of electrophysiological, behavioral and molecular approaches in rats. We are planning to develop optogenetic technique in our future experiments for a better understanding the role of specific neurotransmitters on the effectiveness of brain stimulation in hyper-excitable cells.
Allergic rhinitis (AR) is a chronic inflammatory disease frequently associated with a deficit in learning and memory. Working memory is an important system for decision making and guidance, which depends on interactions between the ventral hippocampus (vHipp) and the prelimbic prefrontal cortex (plPFC). It is still unclear whether AR influences the activity and coupling of these brain areas, which consequently may impair working memory. The current study aimed to examine alterations of the vHipp-plPFC circuit in a rat model of AR. Our results show decreased working memory performance in AR animals, accompanied by a reduction of theta and gamma oscillations in plPFC. Also, AR reduces coherence between vHipp and plPFC in both theta and gamma
Mechanical ventilation (MV) can result in long-term brain impairments that are resistant to treatment. The mechanisms underlying MV-induced brain function impairment remain unclear. Since nasal airflow modulates brain activity, here we evaluated whether reinstating airflow during MV could influence the memory performance of rats after recovery. Rats were allocated into two study groups: one group received rhythmic air-puff into the nasal cavity during MV and a control group that underwent ventilation without air-puff. During MV, air-puffs induced time-locked event potentials in OB, mPFC and vHPC and significantly increased the oscillatory activity at the air-puff frequency. Furthermore, in mPFC and vHPC, (but not in OB), delta and theta osc
Kindling results in abnormal synaptic potentiation and significant impairment in learning and memory. Electromagnetic field (EMF) effects on learning and memory in kindled animals and its effects on hippocampal neural activity are largely unknown. In the current study, the effects of EMF on learning and memory, as well as hippocampal synaptic plasticity, in kindled rats were investigated. EMF (10 m T; 100 Hz) was applied to fully kindled animals one hour/day for a period of one week. The behavioral and electrophysiological studies were performed 24 hours following the EMF application. The kindled rats showed spatial learning deficits during the training phase of the Morris water maze (MWM) test. Moreover, there were increments in es
In spite of long-term intensive scientific research efforts, there are still many issues concerning the mechanisms of epileptogenesis and epilepsy to be resolved. Temporal lobe, in particular hippocampus, is vulnerable to epileptogenic process. Herein, electrical kindling model of temporal lobe were analyzed using proteomic approach. A dramatic decrease in nicotinamide adenine dinucleotide (NAD+) level was exhibited during the kindling procedure in hippocampus. After stage 3, high CD38 expression was detected by qPCR, nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS) and western blot analysis. An increase in expression of CD38/NADase activity was observed during the kindling procedure in hippocampus that represent it as on
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
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
Herein field recordings were utilized to test the effects of a transient period of pentylenetetrazol (PTZ) treatment on theta-burst long-term potentiation (LTP) at the Schaffer collateral-CA1 synapses as well as RT-PCR was used to investigate the effects of the combination of the pharmacological treatment and the theta-burst LTP induction on the expression of NMDA subunit mRNA in hippocampal slices. The slope of field excitatory postsynaptic potential (fEPSP) was unaffected while the population spike amplitude and area were increased by a transient period of PTZ treatment (3?mM, 10?min). After a theta burst, a brief PTZ exposure can lead to an enhancement of LTP as documented by fEPSP recording. The effect can be blocked by a s
Evaluation of changes expression of D1 mGluR1 and CD38 genes after electrical kindling and treatment with low-frequency stimulation in rat-Tarbiat Modares University Journals System-Modares Journal of Biotechnology
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-dimension
Alzheimer's disease (AD) is a complex neurodegenerative disorder with no definite treatment. The expression of miR-29 family is significantly reduced in AD, suggesting a part for the family members in pathogenesis of the disease. The recent emergence of microRNA (miRNA)-based therapeutic approaches is emphasized on the efficiency of miRNA transfer to target cells. The endogenously-made secretory vesicles could provide a biological vehicle for drug delivery. Characteristics such as small sizes, the ability to cross the blood-brain barrier, the specificity in binding to the right target cells, and most importantly the capacity to be engineered as drug carriers have made exosomes desirable vehicles to deliver genetic materials to the central n
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
Despite years of research on pain comorbidity with affective disorders and cognitive deficits, it is still unclear how deficit in attention co-occurs with chronic pain. It is likely that altered neuroplasticity and or dysregulated neurotransmitters induced by chronic pain, at which pain and cognitive processing systems overlap, may have a negative effect on cognitive processing such as attention. One of the main common networks involved in attentional and pain processing is the noradrenergic system originating from the locus coeruleus (LC). We hypothesized that heightened noradrenaline release from LC induced by chronic pain could cause a deficit in visual attention. For this purpose, performance on the 5-choice serial reaction time test (5
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