The effect of serotonin on penicillin-induced epileptiform activity

The Interactions of Resveratrol and Sodium Valproate on Penicillin-Induced Epilepsy Model: Electrophysiological and Molecular Study

Epilepsy represents the most prevalent chronic neurological disease, characterized by spontaneous recurrent seizures. In experimental epilepsy models created by different methods, resveratrol has been demonstrated to reduce epileptiform activity and exhibit neuroprotective properties. A penicillin-induced model of epileptogenesis was used to investigate the effects of resveratrol and its combination with sodium valproate on epileptiform activity. The study design was an in vivo animal experimental study. Forty Wistar-albino rats were divided into five groups, each with eight rats. The groups are categorized as the saline group, penicillin group (only penicillin), resveratrol group, sodium valproate group, and resveratrol + sodium valproate group. ECoG recording was taken for 180 min in all groups and statistically evaluated. GABAα1, mGluR1/mGluR5, NMDAR1 receptor expressions in the hippocampus, and S100B level in serum were measured. The spike frequency decreased statistically to 60th min in the sodium valproate group and 150th min in the resveratrol group. The spike frequency decreased statistically in the 20th min and later measurements of the recording in the resveratrol + sodium valproate group. GABAα1 receptor expression was increased in all groups compared to the penicillin group. mGluR1/mGluR5, NMDAR1 receptor expression was decreased in all groups compared to the penicillin group. Serum S100B level increased in all groups compared to the penicillin group. There was no statistically significant difference in epileptiform activity when resveratrol alone was administered in the penicillin-induced epilepsy model. Resveratrol co-administered with sodium valproate significantly reduced epileptiform activity. Co-administration of the sodium valproate + resveratrol group made the receptor level's highest GABAα1receptor expression at receptors.

Effect of adropin on seizure activity in rats with penicillin-induced epilepsy

BACKGROUND

Epilepsy is a nervous system disease that affects millions of individuals worldwide, and up to 25% of patients have seizures that are resistant to antiepileptic drugs. Therefore, there is a need for the discovery of tolerable, effective antiepileptic agents. This study was aimed to electrophysiologically investigate the effects of the peptide hormone adropin, which was discovered in recent years and whose expression was determined in many organs, on penicillin-induced epileptiform activity in rats.

METHODS

Forty 16-18 weeks old 280-300 g female Wistar albino rats were divided into 5 groups, 8 in each group. 250 min of ECoG recordings were taken from the first group only under anesthesia. Penicillin was given to the second group, L-arginine to the third group, adropin to the fourth group, and these three substances to the fifth group, and records were taken for 250 min and statistically evaluated.

RESULTS

Measurements were made as spike frequency, amplitude values, spike percent change, amplitude percent change. It was determined that the substances given on penicillin-induced acute epilepsy reduced both the number and severity of epileptic seizures. The lowest values were obtained from the L-arginine group, second from the mixture group, and third from the adropin group.

CONCLUSIONS

Although the hormone adropin was not as effective as L-arginine on seizure activity, it can be said that it has a positive effect in terms of antiepileptic activity.

miR-128-3p inhibits the inflammation by targeting MAPK6 in penicillin-induced astrocytes

OBJECTIVE

Epilepsy causes physical and mental damage to patients. As well known, microRNAs (miRNAs) provide therapeutic target potentials for patients with epilepsy. miR-128-3p was previously reported to be downregulated in temporal lobe epilepsy (TLE) patients, however, its detailed function in epilepsy is unknown.

METHODS

Astrocytes function in epilepsy, penicillin-induced astrocytes can be used as a model for seizures in vitro. Currently, the expression levels of mitogen-activated protein kinase 6 (MAPK6), interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) were determined by western blot and reverse transcription-quantitative PCR analyses (RT-qPCR). The expression level of miR-128-3p was evaluated by RT-qPCR. TargetScan 7.1 and dual luciferase reporter assay were used for prediction and verification of interaction between miR-128-3p and MAPK6 3' untranslated region (UTR). Cell viability was detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay.

RESULTS

We found that penicillin-induced decrease in cell viability, and increase of TNF-α/IL-1β in primary astrocytes. There were lower miR-128-3p and higher MAPK6 in penicillin-treated primary astrocytes. miR-128-3p overexpression rescued penicillin-induced reduction of cell viability, and upregulation of TNF-α/IL-1β, which was partially abolished by MAPK6 overexpression.

CONCLUSION

Altogether, miR-128-3p attenuates penicillin-induced cell injury and inflammation in astrocytes by targeting MAPK6, thus providing a protective role in epilepsy.

Immunoreactivity of Muscarinic Acetylcholine M2 and Serotonin 5-HT2B Receptors, Norepinephrine Transporter and Kir Channels in a Model of Epilepsy

Epilepsy is characterized by an imbalance in neurotransmitter activity; an increased excitatory to an inhibitory activity. Acetylcholine (ACh), serotonin, and norepinephrine (NE) may modulate neural activity via several mechanisms, mainly through its receptors/transporter activity and alterations in the extracellular potassium (K⁺) concentration via K⁺ ion channels. Seizures may disrupt the regulation of inwardly rectifying K⁺ (Kir) channels and alter the receptor/transporter activity. However, there are limited data present on the immunoreactivity pattern of these neurotransmitter receptors/transporters and K⁺ channels in chronic models of epilepsy, which therefore was the aim of this study. Changes in the immunoreactivity of epileptogenesis-related neurotransmitter receptors/transporters (M2, 5-HT2B, and NE transporter) as well as Kir channels (Kir3.1 and Kir6.2) were determined in the cortex, hippocampus and medulla of adult Wistar rats by utilizing a Pentylenetetrazol (PTZ)-kindling chronic epilepsy model. Increased immunoreactivity of the NE transporter, M2, and 5-HT2B receptors was witnessed in the cortex and medulla. While the immunoreactivity of the 5-HT2B receptor was found increased in the cortex and medulla, it was decreased in the hippocampus, with no changes observed in the M2 receptor in this region. Kir3.1 and Kir6.2 staining showed increase immunoreactivity in the cerebral cortex, but channel contrasting findings in the hippocampus and medulla. Our results suggest that seizure kindling may result in significant changes in the neurotransmitter system which may contribute or propagate to future epileptogenesis, brain damage and potentially towards sudden unexpected death in epilepsy (SUDEP). Further studies on the pathogenic role of these changes in neurotransmitter receptors/transporters and K⁺ channel immunoreactivity may identify newer possible targets to treat seizures or prevent epilepsy-related comorbidities.

Revisiting the role of neurotransmitters in epilepsy: An updated review

Epilepsy is a neurologicaldisorder characterized by persistent predisposition to recurrent seizurescaused by abnormal neuronal activity in the brain. Epileptic seizures maydevelop due to a relative imbalance of excitatory and inhibitory neurotransmitters. Expressional alterations of receptors and ion channelsactivated by neurotransmitters can lead to epilepsy pathogenesis.

AIMS

In this updated comprehensive review, we discuss the emerging implication of mutations in neurotransmitter-mediated receptors and ion channels. We aim to provide critical findings of the current literature about the role of neurotransmitters in epilepsy.

MATERIALS AND METHODS

A comprehensive literature review was conducted to identify and critically evaluate studies analyzing the possible relationship between epilepsy and neurotransmitters. The PubMed database was searched for related research articles.

KEY FINDINGS

Glutamate and gamma-aminobutyric acid (GABA) are the main neurotransmitters playing a critical role in the pathophysiology of this balance, and irreversible neuronal damage may occur as a result of abnormal changes in these molecules. Acetylcholine (ACh), the main stimulant of the autonomic nervous system, mediates signal transmission through cholinergic and nicotinic receptors. Accumulating evidence indicates that dysfunction of nicotinic ACh receptors, which are widely expressed in hippocampal and cortical neurons, may be significantly implicated in the pathogenesis of epilepsy. The dopamine-norepinephrine-epinephrine cycle activates hormonal and neuronal pathways; serotonin, norepinephrine, histamine, and melatonin can act as both hormones and neurotransmitters. Recent reports have demonstrated that nitric oxide mediates cognitive and memory-related functions via stimulating neuronal transmission.

SIGNIFICANCE

The elucidation of the role of the main mediators and receptors in epilepsy is crucial for developing new diagnostic and therapeutic approaches.

Physical exercise and 5-hydroxytryptophan, a precursor for serotonin synthesis, reduce penicillin-induced epileptiform activity

AIM

Previous studies have shown that 5- hydroxytryptophan (5-HTP) and exercise play an important role in the synthesis of serotonin independently. The effects of the treadmill exercise and 5- hydroxytryptophan (5-HTP) on seizure mechanisms created by epileptiform activity with penicillin model were investigated in rats.

METHOD

A total of 28 male albino Wistar rats were randomly divided into four groups: exercise (Ex), Control (Cnt), 5-hydroxytryptophan (5htp) and 5-hydroxytryptophan + exercise (5htpEx) groups. Treadmill exercise and gavage (25 mg/kg/day) were administered five days a week for ten weeks. Electrocorticogram data were recorded for 3 h at the end of the protocol using the Power-Lab data acquisition system. Spike frequency, amplitude, and latency time were analyzed offline. The significant differences among the groups were evaluated by one-way analysis of variance (ANOVA).

RESULTS

Spike frequency was observed at the highest level from the 20th minute in the Cnt group, and this continued until the end of the recording. The 5-HTP alone group did not affect epileptiform activity. At the 80th minute of penicillin injection, the epileptiform activity in the 5htpEx group decreased significantly compared with the Cnt, and this significance continued until the 110th minute. There was no statistical difference in the amplitude values of the groups. The 5htpEx group was significantly higher than both the Cnt and Ex group in the seizure latency times.

CONCLUSIONS

It was determined that exercise reduced the spike number and delayed seizure significantly by potentiating the effect of 5-HTP. Given that 5-HTP used in combination with exercise can perform useful actions such as reducing seizure sensitivity and consequently improving the quality of life for individuals with epilepsy, it may be a potential candidate for the treatment of epilepsy in nonpharmacological methods.