lignans and Seizures

This paper was designed to investigate anticonvulsant and sedative effects of eudesmin isolated from Acorus tatarinowii. The eudesmin (5, 10, and 20 mg/kg) was administered intraperitoneally (i.p.). The maximal electroshock test (MES) and pentylenetertrazole (PTZ)-induced seizures in male mice were used to evaluate anticonvulsant activities of eudesmin, and sedative effects of eudesmin were evaluated by pentobarbital sodium-induced sleeping time (PST) and locomotor activity in mice. Finally, the mechanisms of eudesmin were investigated by determining contents of glutamic acid (Glu) and gamma-aminobutyric acid (GABA) in epileptic mice, and expressions of glutamate decarboxylase 65 (GAD65), GABAA , Bcl-2, and caspase-3 in the brain of chronic epileptic rats. Results of MES and PTZ tests revealed that eudesmin possesses significant anticonvulsant effects, and the PST and locomotor activity tests demonstrated that eudesmin has significant sedative effects. Furthermore, our study revealed that after treatment with eudesmin, GABA contents increased, whereas Glu contents decreased, and ratio of Glu/GABA decreased. Our results also indicated that expressions of GAD65, GABAA, and Bcl-2 were up-regulated by treating with eudesmin, whereas the caspase-3 obviously was down-regulated. In conclusion, eudesmin has significant anticonvulsant and sedative effects, and the mechanism of eudesmin may be related to up-regulation of GABAA and GAD65 expressions, and anti-apoptosis of neuron the in brain.

Topics: Acorus; Animals; Anticonvulsants; Brain; Caspase 3; Disease Models, Animal; Electroshock; Epilepsy; Furans; gamma-Aminobutyric Acid; Glutamate Decarboxylase; Glutamic Acid; Hypnotics and Sedatives; Lignans; Male; Mice; Mice, Inbred ICR; Motor Activity; Pentobarbital; Plant Extracts; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Sprague-Dawley; Receptors, GABA-A; Seizures

The aim of this study was to evaluate the anti-convulsant effects of magnolol (6, 6', 7, 12-tetramethoxy-2, 2'-dimethyl-1-β-berbaman, C18H18O2) and the mechanisms involved.. Mice were treated with magnolol (20, 40 and 80 mg·kg(-1)) 30 min before injection with pentylenetetrazol (PTZ, 60 mg·kg(-1), i.p.). The anti-seizure effects of magnolol were analysed using seizure models of behaviour, EEG and in vitro electrophysiology and c-Fos expression in the hippocampus and cortex.. Magnolol at doses of 40 and 80 mg·kg(-1) significantly delayed the onset of myoclonic jerks and generalized clonic seizures, and decreased the seizure stage and mortality compared with those of the vehicle-treated animals. EEG recordings showed that magnolol (40 and 80 mg·kg(-1)) prolonged the latency of seizure onset and decreased the number of seizure spikes. The anti-epileptic effect of magnolol was reversed by the GABA(A)/benzodiazepine receptor antagonist flumazenil. Pretreatment with flumazenil decreased the effects of magnolol on prolongation of seizure latency and decline of seizure stage. In a Mg(2+)-free model of epileptiform activity, using multi-electrode array recordings in mouse hippocampal slices, magnolol decreased spontaneous epileptiform discharges. Magnolol also significantly decreased seizure-induced Fos immunoreactivity in the piriform cortex, dentate gyrus and hippocampal area CA1. These effects were attenuated by pretreatment with flumazenil.. These findings indicate that the inhibitory effects of magnolol on epileptiform activity were mediated by the GABA(A) /benzodiazepine receptor complex.

Topics: Animals; Anticonvulsants; Behavior, Animal; Biphenyl Compounds; Cerebral Cortex; Dose-Response Relationship, Drug; Electroencephalography; Excitatory Postsynaptic Potentials; Hippocampus; Lignans; Magnolia; Male; Mice; Mice, Inbred Strains; Molecular Structure; Plant Bark; Receptors, GABA-A; Seizures

The effects of honokiol and magnolol, two major bioactive constituents of the bark of Magnolia officinalis, on Ca(2+) and Na(+) influx induced by various stimulants were investigated in cultured rat cerebellar granule cells by single-cell fura-2 or SBFI microfluorimetry. Honokiol and magnolol blocked the glutamate- and KCl-evoked Ca(2+) influx with similar potency and efficacy, but did not affect KCl-evoked Na(+) influx. However, honokiol was more specific for blocking NMDA-induced Ca(2+) influx, whereas magnolol influenced with both NMDA- and non-NMDA activated Ca(2+) and Na(+) influx. Moreover, the anti-convulsant effects of these two compounds on NMDA-induced seizures were also evaluated. After honokiol or magnolol (1 and 5 mg/kg, i.p.) pretreatment, the seizure thresholds of NMRI mice were determined by tail-vein infusion of NMDA (10 mg/ml). Data showed that both honokiol and magnolol significantly increased the NMDA-induced seizure thresholds, and honokiol was more potent than magnolol. These results demonstrated that magnolol and honokiol have differential effects on NMDA and non-NMDA receptors, suggesting that the distinct therapeutic applications of these two compounds for neuroprotection should be considered.

Topics: Analysis of Variance; Animals; Anti-Anxiety Agents; Biphenyl Compounds; Calcium; Cells, Cultured; Cerebellum; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Interactions; Excitatory Amino Acid Agonists; Excitatory Amino Acid Antagonists; Ion Channels; Lignans; Mice; N-Methylaspartate; Neurons; Platelet Aggregation Inhibitors; Potassium Chloride; Quinoxalines; Rats; Rats, Sprague-Dawley; Seizures; Sodium