Lamotrigine effects sensorimotor gating in WAG/Rij rats

Prepulse inhibition (PPI) is a measurable form of sensorimotor gating. Disruption of PPI reflects the impairment in the neural filtering process of mental functions that are related to the transformation of an external stimuli to a response. Impairment of PPI is reported in neuropsychiatric illnesses such as schizophrenia, Huntington's disease, Parkinson's diseases, Tourette syndrome, obsessive compulsive disorder, and temporal lobe epilepsy with psychosis. Absence epilepsy is the most common type of primary generalized epilepsy. Lamotrigine is an antiepileptic drug that is preferred in absence epilepsy and acts by stabilizing the voltage-gated sodium channels.

In this study, we have compared WAG-Rij rats (genetically absence epileptic rats) with Wistar rats, in order to clarify if there is a deficient sensorimotor gating in absence epilepsy, and have examined the effects of lamotrigine (15, 30 mg/kg, i.p.) on this phenomenon.

Depletion in PPI percent value is accepted as a disruption in sensory-motor filtration function. The difference between the Wistar and WAG/Rij rats has been evaluated with the student t test and the effects of lamotrigine on the PPI percent have been evaluated by the analysis of variance (ANOVA) post-hoc Dunnett's test.

The PPI percent was low in the WAG/Rij rats compared to the controls (P<0.0001, t:9,612). Although the PPI percent value of the control rats was not influenced by lamotrigine, the PPI percent value of the WAG/Rij rats was raised by lamotrigine treatment (P<0.0001, F:861,24).

As a result of our study, PPI was disrupted in the WAG/Rij rats and this disruption could be reversed by an antiepileptic lamotrigine.