Antiepileptic potential of Anisomeles indica (Linn.) Kuntze aerial parts in pentylenetetrazole-induced experimental convulsions in Wistar rats.

The chloroform (4.20% w/w), ethyl acetate (4.23% w/w) and aqueous decoction (12.11% w/w) extracts of the aerial parts of A. indica were screened for the antiepileptic activity against maximal electroshock (MES) model and pentylenetetrazole (PTZ) models at  doses of 200, 400 mg/kg, po once. Phenytoin and diazepam (25 and 2 mg/kg, ip) were used as standard drugs in MES and PTZ model, respectively. Further, ethyl acetate extract (active extract) was fractionated into flavonoid and tannin fraction, which were subsequently evaluated for the antiepileptic potential against both MES and PTZ models at a dose of 50 mg/kg, po. Pretreatment with ethyl acetate extract 200, 400 mg/kg, po, for 1 week showed significant antiepileptic activity against PTZ induced convulsions only. Isolated flavonoid fraction showed more potent antiepileptic activity as compared to ethyl acetate extract, without any neurotoxic effect. However, tannin fraction did not produce antiepileptic activity against PTZ induced convulsions. It may be concluded that the flavonoids fraction of ethyl acetate extract of aerial parts of A. indica, but not the aqueous decoction has antiepileptic potential, without producing neurotoxic effects.

Pro-convulsant effect of cefazolin sodium against pentylenetetrazol- or picrotoxin-induced convulsions in mice.

Cefazolin injection (3000 mg/kg, i.v.) in mice showed several behavioral excitations such as wild running, jumping, rolling, and finally undergoing severe convulsions followed by death. It's lower doses (500-2000 mg/kg, i.v.) were unable to produce any convulsions or behavioral excitations in mice. However, cefazolin (500 or 1000 mg/kg, i.v.) when administered before different doses of pentylenetetrazol (PTZ; 40 or 60 mg/kg, i.p.) or picrotoxin (PTX; 4 or 8 mg/kg, i.p.), it produced severe tonic-clonic convulsions in mice. The convulsions or behavioral excitations produced by 3000 mg/kg, i.v. cefazolin was also reversed by different doses of diazepam (0.5-2 mg/kg, i.p.) further proving the GABAergic modulatory effect of cefazolin. The results conclude the pro-convulsant action of cefazolin on PTZ- or PTX-induced convulsions, and further confirm the clinical reports.

Anti-seizure efficacy of nimodipine in pentylenetetrazole and kainic acid combined seizure models in mice.

The present study aimed at establishing two models of experimental seizures by combination treatment with subconvulsive doses of PTZ and kainic acid in adult male mice and evaluating the modulatory role of cerebroselective dihydropyridine calcium channel blocker, nimodipine. The CD50 +/- SEM value for PTZ was found to be 20.00 +/- 0.92 mg/kg, ip in kainic acid (administered at per se subconvulsive dose of 1.00 mg/kg, ip) pretreated mice while CD50 +/- SEM value for kainic acid was found to be 0.30 +/- 0.08 mg/kg, ip in PTZ (administered at per se subconvulsive dose of 30.00 mg/kg, ip) pretreated mice. Nimodipine (5.00 mg/kg, ip) significantly protected the mice from seizure in both of the combination in vivo seizure models. The results suggested synergistic interaction between PTZ and kainic acid at subconvulsive dose combination while the protective efficacy of nimodipine suggested the role of calcium ion as an important mediator for the genesis of seizures.