Neurochemical evidence based suggested therapy for safe management of epileptogenesis.

Most of the clinically available antiepileptic drugs have only antiseizure effects and are reported unable to prevent epileptogenesis. In the past decade, several drugs underwent clinical trials for management of epileptogenesis, but none of the drugs tested was found effective. One of the major lacunas is availability of appropriate preclinical approaches to delineate mechanisms of epileptogenesis. Thus, the present study attempts to suggest a neurochemistry based approach for safe management of epileptogenesis. The altered neurochemical milieu in amygdala, cortex and hippocampus areas of the mice brain in naïve, kindled and kindling resistant animals has been delineated. The endogenous natural antiepileptogenic neurochemical defense mechanism observed in kindling resistant animals may uncover neurochemical mechanisms of epileptogenesis and in turn suggest us novel interventions for safe management of epileptogenesis. The kindling epileptogenesis was carried out in two month old male Swiss albino mice by administering subconvulsive pentylenetetrazole (35mg/kg; i.p.) at an interval of 48±2h for 42days. 2h after the last pentylenetetrazole injection, the animals were subjected to behavioral evaluations. Four hours after behavioral evaluation, all animals were euthanized and discrete parts of brain (amygdala, cortex and hippocampus) were harvested for neurochemical analysis. Results revealed that 60% of animals responded to kindling as observed with decreased seizure threshold, while the rest were found resistant. The kindled animals were found to be associated with anxiety, depression and cognitive impairment; while in kindling resistant animals no such behavioral deficits were observed. The neurochemical analysis revealed that in kindled animals altered glutamate-GABA neurotransmission, and decreased taurine, glycine, d-serine, monoamine levels with elevated indoleamine 2,3-dioxygenase activity were observed, which may be convicted for progression of kindling epileptogenesis. However, in kindling resistant animals elevated GABA, taurine, tryptophan, serotonin, glycine, and d-serine levels with decreased indoleamine 2,3-dioxygenase activity were observed as natural endogenous antiepileptogenic mechanisms, which may be foreseen as safe pharmacological targets for management of epileptogenesis.

Kaur N ，Singh T ，Kumar S ，Goel RK ... -  《-》

Evidence in support of using a neurochemistry approach to identify therapy for both epilepsy and associated depression.

The present study aimed to develop a neurochemistry-based single or adjuvant therapy approach for comprehensive management of epilepsy and associated depression employing pentylenetetrazole-kindled animals. Kindling was induced in two-month-old male Swiss albino mice by administering a subconvulsant pentylenetetrazole dose (35mg/kg, i.p.) at an interval of 48±2h. These kindled animals were treated with saline and sodium valproate (300mg/kg/day, i.p.) for 15days. Except for the naïve group, all other groups were challenged with pentylenetetrazole (35mg/kg, i.p.) on days 5, 10, and 15 to evaluate the seizure severity. Depression was evaluated in all experimental groups after normalization of locomotor activity, using tail suspension and forced swim test on days 1, 5, 10, and 15. Four hours after behavioral evaluations on day 15, all animals were euthanized to collect their serum and discrete brain parts. Corticosterone levels were estimated in all the experimental groups as a marker of a dysregulated hypothalamus pituitary adrenal axis. Neurochemical alterations (norepinephrine, dopamine, tryptophan, kynurenine, serotonin, glutamate, GABA, and total nitrate levels) were also estimated in the cortical and hippocampal areas of the mouse brain. Results revealed that saline-treated kindled animals were associated with significant depression and altered neurochemical milieu in comparison with naïve animals. Chronic valproate treatment in kindled animals significantly reduced seizure severity score bud did not ameliorate associated depression or completely restore altered biochemical and neurochemical milieu. Based on the observation of neurochemical changes in all the groups, we propose that restoration of altered neurochemical milieu, elevated indoleamine 2,3-dioxygenase enzyme activity, and corticosterone levels using pharmacological tools with/out valproic acid may be explored for management of both epilepsy and comorbid depression.

Singh T ，Goel RK 《-》

Chronic 5-HT(3) receptor antagonism ameliorates seizures and associated memory deficit in pentylenetetrazole-kindled mice.

Our previous studies have suggested a strong involvement of serotonergic innervations in epileptogenesis and associated memory impairment. Several studies have suggested that the modulation of 5-HT3 receptors could serve as a promising tool for the management of epilepsy and memory deficit. The present study was envisaged to confirm this hypothesis. In this study, kindling was induced in male Swiss Albino mice using a subconvulsive dose of pentylenetetrazole (PTZ) (35mg/kg at 48±2h). Once the animals were kindled, they were treated with a vehicle, ondansetron (0.1, 0.5, 1mg/kg/day; i.p.), m-chlorophenylbiguanide (m-CPBG) (1mg/kg/day; i.p.), and ondansetron+m-CPBG for 20days. On days 5, 10, 15, and 20, they were administered a PTZ challenging dose (35mg/kg) to assess the seizure severity score; thereafter, memory was evaluated. After behavioral assessment on day 20, the animals were sacrificed and their brains were isolated to estimate cortical and hippocampal neurotransmitter levels (glutamate and gamma aminobutyric acid (GABA) by the high-performance liquid chromatography with the fluorescence detection method, and the nitrite level and acetylcholinesterase (AChE) activity by the microplate reader method). Ondansetron treatment significantly reduced the seizure severity and improved the acquisition performance in a dose-dependent manner. Neurochemical analysis suggested that ondansetron treatment significantly reduced the nitrite level and AChE activity in the cortex as well as in the hippocampus. The outcome of this study suggests the reduction in AChE activity and the nitrite level could be considered as protective mechanisms of ondansetron for amelioration of PTZ kindling and associated memory deficit.

Mishra A ，Goel RK 《-》

Resveratrol suppressed seizures by attenuating IL-1β, IL1-Ra, IL-6, and TNF-α in the hippocampus and cortex of kindled mice.

Hoda U ，Agarwal NB ，Vohora D ，Parvez S ，Raisuddin S ... -  《-》

Effect of lamotrigine on seizure development in a rat pentylenetetrazole kindling model.

Chen Y ，He X ，Sun Q ，Fang Z ，Zhou L ... -  《-》