The Effects of Adenosinergic Modulation on Cytokine Levels in a Pentylenetetrazole-Induced Generalized Tonic-Clonic Seizure Model.

OBJECTIVE: It has been suggested that the adenosinergic system and cytokines play a role in the pathogenesis of epilepsy. Although the role of the adenosinergic system in the modulation of seizure activity is well known, the mechanism of this modulation needs to be described in detail. We performed this study to determine the contribution of the proinflammatory cytokines to the generalized seizure activity during adenosine and caffeine treatment. METHODS: We induced generalized tonic-clonic seizures with the administration of 60 mg/kg pentylenetetrazole (PTZ) in male Wistar Albino rats. Adenosine (500 mg/kg) or caffeine (5 mg/kg) was administered before PTZ injection. We monitored seizure activity and then determined the TNF-α, IL-1ß, and IL-6 levels in the cortical and thalamic brain regions of rats by ELISA. RESULTS: Adenosine pretreatment significantly extended seizure latency (p < 0.05), but did not affect seizure duration and entry time to stage 4 seizure. Caffeine pretreatment did not change seizure latency and seizure duration. PTZ treatment did not change brain cytokine levels significantly (p > 0.05) compared to the control group. Whereas adenosine pretreatment decreased brain TNF-α, IL-1ß, and IL-6 levels significantly (p < 0.05), caffeine pretreatment reduced brain cytokine levels slightly but nonsignificantly (p > 0.05). CONCLUSION: Our results show that there is a clear relation between adenosinergic system and brain tissue cytokine levels. Our findings indicated that TNF-α, IL-1ß, and IL-6 participate in the pathogenesis of generalized seizures, and the inhibition of TNF-α, IL-1ß, and IL-6 with adenosinergic modulation may decrease seizure severity.

Endoplasmic reticulum stress produced by Thapsigargin affects the occurrence of spike-wave discharge by modulating unfolded protein response pathways and activating immune responses in a dose-dependent manner.

The Endoplasmic Reticulum (ER) is associated with many cellular functions, from post-transcriptional modifications to the proper folding of proteins, and disruption of these functions causes ER stress. Although the relationship between epileptic seizures and ER stress has been reported, the contribution of ER stress pathways to epileptogenesis is still unclear. This study aimed to investigate the possible effects of ER stress-related molecular pathways modulated by mild- and high-dose Thapsigargin (Tg) on absence epileptic activity, CACNA1H and immune responses in WAG/Rij rats. For this purpose, rats were divided into four groups; mild-dose (20 ng) Tg, high-dose (200 ng) Tg, saline, and DMSO and drugs administered intracerebroventriculary. EEG activity was recorded for 1 h and 24 h after drug administration following the baseline recording. In cortex and thalamus tissues, GRP78, ERp57, GAD153 protein changes (Western Blot), Eif2ak3, XBP-1, ATF6, CACNA1H mRNA expressions (RT-PCR), NF-κB and TNF-α levels (ELISA) were measured. Mild-dose-Tg administration resulted in increased spike-wave discharge (SWD) activity at the 24th hour compared to administration of saline, and high-dose-Tg and it also significantly increased the amount of GRP78 protein, the expression of Eif2ak3, XBP-1, and CACNA1H mRNA in the thalamus tissue. In contrast, high-dose-Tg administration suppressed SWD activity and significantly increased XBP-1 and ATF6 mRNA expression in the thalamus, and increased NF-κB and TNF-α levels. In conclusion, our findings indicate that Tg affects SWD occurrence by modulating the unfolded protein response pathway and activating inflammatory processes in a dose-dependent manner.

Antagonism of adenosinergic system decrease SWD occurrence via an increment in thalamic NFkB and IL-6 in absence epilepsy.

Epilepsy is a major pathological condition, characterized by recurrent seizures and affecting approximately 1% of the population. Many studies have shown a relationship between epilepsy and inflammation. The adenosinergic system contributes to inflammation and epilepsy by regulating the release of neurotransmitters through its various receptors. This study investigates the effect of agonist and antagonist of adenosinergic system on seizure activity and cytokine levels in the WAG/Rij strain, a genetic animal model of absence epilepsy. The WAG/Rij rats used in our study were assigned to saline, Tween 20, adenosine, and caffeine groups. Tripolar electrodes were implanted on the skull, and EEG activities recorded for 3 h. ELISA was used to determine the NFkB, TNF-α, IL-1ß, and IL-6 levels in the cortical and thalamic brain regions, as well as the TNF-α, IL-1ß, and IL-6 levels in the blood samples. Administration of caffeine to rats resulted in a decreased SWD number at 30 and 60 min as determined by EEG recording after baseline (p < .05), and a significant increase in NFkB and IL-6 levels in the thalamic tissue (p < .05). Administration of adenosine to rats did not change seizures and cytokine levels. Our results show that an increase in thalamic IL-6 and NFkB levels may related with a decrement in absence epilepsy. This study clearly shows the contribution of adenosinergic system in absence seizure in WAG/Rij rats. These results also support the importance of the thalamus on occurrence of SWD in the thalamocortical loop.