ABSTRACT
Chemically different classes of calcium channel blockers were examined in rats for their effects on behavior, tolerability and protection against maximal electroshock seizures (MES) and pentylenetetrazol (PTZ) induced seizures. In MES test at doses (mg/kg, ip) that were devoid of side effects, felodipine, 50, afforded 100% protection, while nimodipine, 5; pimozide, 10; and thioridazine, 25, showed 50 to 66% protection. Nifedipine, 10, and diltiazem, 50, showed 30 and 66% protection respectively, but were associated with side effects. Verapamil and loperamide were ineffective against MES and PTZ induced seizures. Nimodipine, 1 mg/kg, ip, was the most potent agent and produced 100% protection against PTZ. Equieffective doses were pimozide, 25, felodipine, 50, and thioridazine, 50. The rest of the calcium channel blockers showed marginal to moderate activity against chemoshock. The data obtained suggest that some calcium channel blockers possess anticonvulsant activity and may be considered as adjuvant therapeutic agents in epileptics refractory to conventional antiepileptic medication.
Subject(s)
Animals , Anticonvulsants/therapeutic use , Calcium Channel Blockers/therapeutic use , Electroshock/adverse effects , Female , Male , Pentylenetetrazole/toxicity , Rats , Rats, Inbred Strains , Seizures/chemically inducedABSTRACT
Dopamine (DA) receptor supersensitivity was induced in albino rats by haloperidol (5 mg/kg, ip day, for 18 days) and after 48 hr carbamazepine (CBZ) was administered in graded doses. The animals were subjected to Maximal Electroshock Seizures (MES) test, Minimal Electroconvulsive Threshold (MET) test and Pentylenetetrazole (PTZ)-induced convulsions test. Haloperidol pretreatment marginally increased the effect of CBZ against PTZ induced seizures, but not against electrically induced seizures (MES and MET tests).