A study of the effects of lamotrigine on mice using two convulsive tests.

UNLABELLED The AIM was to study the effects of lamotrigine on bicuculline and pentylenetetrazol models of epilepsy. MATERIAL AND METHODS Mice divided in 8 groups (n = 6) were pretreated intraperitoneally 30 min before pentylenetetrazol (50 mg/kg) or bicuculline (1 mg/kg) with saline 0.1 ml/10 g body weight or lamotrigine 10 mg/kg, 15 mg/kg or 20 mg/kg, respectively. The seizure intensity and latency to the seizures 60 min after bicuculline or pentylenetetrazol injection were observed. The following scale for seizure intensity was used: 1 - excitation; 2 - body tremor; 3 - clonic seizures of forelimbs; 4 - heavy clonic seizures with rotations; 5 - tonic seizures of forelimbs; 6 - tonic seizures of limbs. RESULTS The controls showed bicuculline-induced seizure intensity up to 5. Lamotrigine in the higher doses used decreased the seizure intensity (p <0.05). Lamotrigine in all doses studied did not change the latency period of the first bicuculline seizure compared with the control. Controls treated with pentylenetetrazol showed seizure intensity up to 4. Lamotrigine in the highest dose decreased the pentylenetetrazol-induced seizure intensity (p < 0.05). Lamotrigine in all studied doses increased the latency to the first pentylenetetrazol-induced seizure compared with the controls (p < 0.05). Both convulsing drugs influence the brain GABA-ergic transmitter system by competitively blocking GABAA receptors. Lamotrigine inhibits glutamate transmission and sodium channels. Both neurotransmissions - glutamate and GABA are closely related in seizure control. The CONCLUSION is that lamotrigine has an anticonvulsive effect on both bicuculline and pentylenetetrazol seizure models, suppressing seizure intensity and influencing the latency to the first seizure.