Pharmacological and biochemical analysis of interactions between N-acetylcysteine and some antiepileptic drugs on experimental seizures in mice

Protective effects of maternal administration of curcumin and hesperidin in the rat offspring following repeated febrile seizure: Role of inflammation and TLR4

Neuroinflammation has a key role in seizure generation and perpetuation in the neonatal period, and toll-like receptor 4 (TLR4) pathway has a prominent role in neuroinflammatory diseases. Administration of antioxidants and targeting TLR4 in the embryonic period may protect rat offspring against the next incidence of febrile seizure and its harmful effects. Curcumin and hesperidin are natural compounds with anti-inflammatory and antioxidant properties and have an inhibitory action on TLR4 receptors. We evaluated the effect of maternal administration of curcumin and hesperidin on infantile febrile seizure and subsequent memory dysfunction in adulthood. Hyperthermia febrile seizure was induced on postnatal days 9-11 on male rat pups with 24 h intervals, in a Plexiglas box that was heated to ~45 °C by a heat lamp. We used enzyme-linked immunosorbent assay, Western blotting, malondialdehyde (MDA), and glutathione (GSH) assessment for evaluation of inflammatory cytokine levels, TLR4 protein expression, and oxidative responses in the hippocampal tissues. For assessing working memory and long-term potentiation, the double Y-maze test and Schaffer collateral-CA1 in vivo electrophysiological recording were performed, respectively Our results showed that curcumin and hesperidin decreased TNF-α, IL-10, and TLR4 protein expression and reversed memory dysfunction. However, they did not provoke a significant effect on GSH content or amplitude and slope of recorded fEPSPs in the hippocampus. In addition, curcumin, but not hesperidin, decreased interleukin-1β (IL-1β) and MDA levels. These findings imply that curcumin and hesperidin induced significant protective effects on febrile seizures, possibly via their anti-inflammatory and antioxidant properties and downregulation of TLR4.

Raloxifene potentiates the effect of fluoxetine against maximal electroshock induced seizures in mice

The evidence to guide clinicians regarding rationale polytherapy with current antiepileptic drugs (AEDs) is lacking, and current practice recommendations are largely empirical.  The excessive drug loading with combinatorial therapies of existing AEDs are associated with escalated neurotoxicity, and that emergence of pharmacoresistant seizures couldn't be averted. In pursuit of judicious selection of novel AEDs in combinatorial therapies with mechanism based evidences, standardized dose of raloxifene, fluoxetine, bromocriptine and their low dose combinations, were experimentally tested for their impact on maximal electroshock (MES) induced tonic hind limb extension (THLE) in mice. Hippocampal neuropeptide Y (NPY) levels, oxidative stress and histopathological studies were undertaken. The results suggest the potentiating effect of 4 mg/kg raloxifene on 14 mg/kg fluoxetine against MES induced THLE, as otherwise monotherapy with 4 mg/kg raloxifene was unable to produce an effect. The results also depicted better efficacy than carbamazepine (20 mg/kg), standard AED. Most profoundly, MES-induced significant (P < 0.001) reduction in hippocampal NPY levels, that were escalated insignificantly with the duo-drug combination, suggesting some other mechanism in mitigation of electroshock induced seizures. These results were later corroborated with assays to assess oxidative stress and neuronal damage. In conclusion, the results demonstrated the propitious therapeutic benefit of duo-drug low dose combination of drugs; raloxifene and fluoxetine, with diverse mode of actions fetching greater effectiveness in the management of generalized tonic clonic seizures (GTCS).

Effects of Lycopene and Sodium Valproate on Pentylenetetrazol-Induced Kindling in Mice

Sodium valproate and tomato extract have been studied in different experimental models of epilepsy individually. The aim of the present study was to evaluate the effect of lycopene on the antiepileptic effects of sodium valproate against pentylenetetrazol-induced kindling in mice. Swiss albino mice of either sex were randomly divided into 5 groups, with each group containing 8 mice. These groups were treated with pentylenetetrazol (45 mg/kg on days 8, 10, and 12 and 70 mg/kg on day 14 day, i.p.); sodium valproate (200 mg/kg, p.o.) + pentylenetetrazol; lycopene (2 mg/kg, p.o.) + sodium valproate (200 mg/kg, p.o.) + pentylenetetrazol; and lycopene (4 mg/kg, p.o.) + sodium valproate (200 mg/kg, p.o.) + pentylenetetrazol, for 14 days, respectively. After treatment, the animals were observed for 30 minutes for behavioral analysis. Subsequently, the animals were sacrificed, and their brain was removed for the biochemical estimations of thiobarbituric acid reactive substances, catalase, superoxide dismutase activity, reduced glutathione, and gamma-aminobutyric acid. Significant pentylenetetrazol-induced seizure was characterized by alteration in the seizure score and latency as well as a significant increase in the levels of brain thiobarbituric acid reactive substances and a significant decrease in reduced glutathione, catalase, superoxide dismutase, and gamma-aminobutyric acid levels. Treatment with sodium valproate and lycopene significantly restored the seizure score, latency, thiobarbituric acid reactive substance, reduced glutathione, catalase, superoxide dismutase, and gamma-aminobutyric acid levels near to normal compared to pentylenetetrazol. The present study provides experimental evidence that a combination therapy of lycopene along with sodium valproate attenuated seizure and oxidative stress against pentylenetetrazol-induced kindling in mice.

Acute and Chronic Effects of N-acetylcysteine on Pentylenetetrazole-induced Seizure and Neuromuscular Coordination in Mice

BACKGROUND

N-acetylcysteine (NAC) has been indicated against experimental seizures, but with relatively inconclusive results. This study was undertaken to evaluate whether NAC exerts a dose-dependent anticonvulsant effect and to determine NAC safe therapeutic dose range and its muscle-relaxant activity in both acute and chronic uses.

METHODS

Following intraperitoneal (i.p.) administration of N-acetylcysteine acutely (50-300 mg/kg) or chronically for 8 days (25-300 mg/kg), mice were injected with PTZ (90 mg/kg, i.p.) and latency times to the onset of myoclonic and clonic seizures and protection against death were recorded. Changes in body weight and mortality rate were considered as parameters for drug safety. The muscle-relaxant activity of NAC was assessed by rotarod test.

RESULTS

Acute and chronic treatment with NAC delayed latency times to myoclonic and clonic seizures in a dose-dependent manner, but with no significant prevention against PTZ-induced death. Chronic administration of 300 mg/kg NAC was fully lethal while lower doses (100 and 150 mg/kg) resulted in a significant weight loss and decreased stay time on rotarod. Acute treatment with NAC had no significant effect on stay time on rotarod at all studied doses.

CONCLUSION

NAC exerts a dose-dependent anticonvulsant effect in acute and chronic uses, with no muscle relaxant activity. NAC has higher efficacy in preventing seizure in chronic than acute treatment, but its chronic use at higher doses of 75 mg/kg may be associated with side effects and/or toxicity. These findings suggest that low doses of NAC may have a potential use as a prophylactic treatment for absence seizure in human.

Oxidative stress is not involved in motion sickness in mice

AIMS

Some indirect evidences indicate a possible correlation between oxidative stress and motion sickness. The aim of this research was to investigate whether oxidative stress contributing to motion sickness in mice or not.

METHODS

We examined the mRNA levels of peroxiredoxin 6 (PRDX6), catalase, and enzyme superoxide dismutase 1 (SOD1); reactive oxygen species (ROS); and total antioxidant capacity and SOD activity in different brain regions after rotary stimulation. Mice motion sickness index was recorded after rotation when pretreated with paraquat, vitamin C, or vitamin E.

RESULTS

The ROS level and antioxidant capacity were both increased in cerebellum plus brainstem (CB) after rotation, a critical region determines motion sickness. However, manipulation of oxidants or antioxidants using pharmacological method in vivo had no influence on motion sickness index in mice.

CONCLUSION

Oxidative stress is not involved in the development of motion sickness in mice.