Allopurinol and ellagic acid decrease epileptiform activity and the severity of convulsive behavior in a model of status epilepticus.

Background: During status epilepticus, severe seizures can occur, generating recurrent cycles of excitotoxicity and oxidative stress that cause neuronal damage and cell death. The administration of agents with antioxidant properties represents a therapeutic alternative aimed at reducing the severity of status epilepticus and mitigating the neurobiological consequences that precede them.

Objective: The objective of this work was to evaluate the antiseizure effect of the antioxidants allopurinol (ALL) and ellagic acid during status epilepticus induced by pilocarpine (PILO).

Ellagic acid and allopurinol decrease HO concentrations, epileptiform activity and astrogliosis after status epilepticus in the hippocampus of adult rats.

Status epilepticus (SE) can result in an overproduction of hydrogen peroxide (HO), which contributes to oxidative stress and brain injury during different phases of epileptogenesis and seizures. The purpose of this study was to evaluate the effects of ellagic acid and allopurinol administered after SE on HO concentrations, electrical activity and GFAP immunoreactivity in the hippocampus of rats evaluated on Day 18 after SE. HO levels were measured using an online technique with high temporal resolution and simultaneous electrical activity recording.

Hydrogen peroxide extracellular concentration in the ventrolateral medulla and its increase in response to hypoxia in vitro: Possible role of microglia.

Hydrogen peroxide (HO) is a messenger involved in both damaging neuroinflammatory responses and physiological cell communication. The ventrolateral medulla, which regulates several vital functions including breathing and blood pressure, is highly influenced by hydrogen peroxide, whose extracellular levels could be determined by hypoxia and microglial activity, both of which modulate ventrolateral medulla function. Therefore, in this study we aimed to test whether different patterns of hypoxia and/or putative microglial modulators change extracellular hydrogen peroxide in the ventrolateral medulla by using an enzymatic reactor online sensing procedure specifically designed for this purpose.

γ-Aminobutyric acid quantification in small volume biological samples through enzymatically induced electrochemiluminescence.

γ-Aminobutyric acid (GABA) is a well-known neurotransmitter that regulates inhibitory neurotransmission in the mammalian central nervous system and participates in several processes outside the brain. A reliable quantification method is needed to determine its role in different physiological and pathological conditions. However, GABA measurements have several challenges because GABA is neither fluorescent nor electroactive, and it is difficult to detect using enzymatic reactions because no oxidases or dehydrogenases have been identified.

A novel online fluorescence method for in-vivo measurement of hydrogen peroxide during oxidative stress produced in a temporal lobe epilepsy model.

Status epilepticus (SE) can result in an overproduction of hydrogen peroxide (H2O2), which contributes to oxidative stress and brain injury during different phases of epileptogenesis and seizures. In this study, we measured the extracellular H2O2 concentration in the rat hippocampus in a temporal lobe epilepsy model. A new fluorescent technique for measuring H2O2 in vivo simultaneously with electroencephalography recording was tested.

A microdialysis and enzymatic reactor sensing procedure for the simultaneous registration of online glutamate measurements at high temporal resolution during epileptiform activity.

Glutamate measurement in microdialysis samples has primarily been determined using HPLC methods, and several attempts have been made to establish a relationship between this neurotransmitter and EEG activity during altered brain function, such as epilepsy. However, classic microdialysis methods lack high temporal resolution. In this study, a new alternative is proposed to improve the time resolution and thus obtain a better understanding of the dynamics of Glu and its relationship with epileptiform activity.

An update of the classical and novel methods used for measuring fast neurotransmitters during normal and brain altered function.

To understand better the cerebral functions, several methods have been developed to study the brain activity, they could be related with morphological, electrophysiological, molecular and neurochemical techniques. Monitoring neurotransmitter concentration is a key role to know better how the brain works during normal or pathological conditions, as well as for studying the changes in neurotransmitter concentration with the use of several drugs that could affect or reestablish the normal brain activity. Immediate response of the brain to environmental conditions is related with the release of the fast acting neurotransmission by glutamate (Glu), γ-aminobutyric acid (GABA) and acetylcholine (ACh) through the opening of ligand-operated ion channels.

Increase in the extracellular glutamate level during seizures and electrical stimulation determined using a high temporal resolution technique.

Background: Glutamate has been measured using different methods to determine its role under normal and pathological conditions. Although microdialysis coupled with HPLC is the preferred method to study glutamate, this technique exhibits poor temporal resolution and is time consuming. The concentration of glutamate in dialysis samples can be measured via glutamate oxidase using the Amplex Red method.

Evaluation of behavioral parameters and mortality in a model of temporal lobe epilepsy induced by intracerebroventricular pilocarpine administration.

The pilocarpine model of temporal lobe epilepsy (TLE) is a useful tool that is used to investigate the mechanisms underlying the generation and maintenance of seizures. Although this model has been modified significantly to reduce mortality and to promote the appearance of spontaneous recurrent seizures, to date, no detailed evaluation has been performed of the behavioral parameters and mortality in TLE induced by intracerebroventricular pilocarpine administration; therefore, this was the goal of the present study. A single dose of pilocarpine hydrochloride (2.

An algorithm for on-line detection of high frequency oscillations related to epilepsy.

Recent studies suggest that the appearance of signals with high frequency oscillations components in specific regions of the brain is related to the incidence of epilepsy. These oscillations are in general small in amplitude and short in duration, making them difficult to identify. The analysis of these oscillations are particularly important in epilepsy and their study could lead to the development of better medical treatments.

Effect of early glutamate exposure on EAAT-3 and GAT-1 protein expression in cells of the dentate gyrus and CA1 region of the adult rat hippocampus.

Background And Aims: Glutamate and GABA transporters are cell surface proteins localized on neurons and glial cells that mediate the reuptake of glutamate and GABA from the extracellular space. In different models of the acquisition of epilepsy, important changes in the expression of these transporters have been demonstrated, although to date no such studies have been performed using the monosodium glutamate (MSG)-induced seizure model in neonatal rats.

Methods: Following repeated MSG administration, we used immunofluorescence techniques to quantify the number of cells expressing the EAAT-3 and GAT-1 transporters at postnatal days (PD) 14 and 60 in the dentate gyrus (DG) and CA1 region of the hippocampus.