Anti-convulsant effect of electrical stimulation and lesioning of the anterior thalamic nucleus on kainic acid-induced focal limbic seizure in rats.

Purpose: We examined the effect of electrical stimulation and lesioning of the anterior nucleus of the thalamus (ANT) on focal limbic seizures induced by intraamygdaloid kainic acid (KA) injection in a rat model. To address the mechanism underlying these anti-convulsant actions, cerebral glucose metabolism following ANT electrical stimulation and lesioning was also assessed.

Methods: Wistar rats were divided into five major groups: control, unilateral and bilateral ANT electrical stimulation, and unilateral and bilateral ANT lesioning. After KA injection, average clinical-seizure frequencies in each group were measured. Local cerebral glucose utilization (LCGU) was also measured using [(14)C] 2-deoxyglucose autoradiography in three groups: control, ANT electrical stimulation and ANT lesioning.

Results: Animals subjected to ANT electrical stimulation and lesioning exhibited significantly decreased mean seizure frequency and secondary generalized seizure frequency, compared with control-animals. In control-group, LCGU was markedly increased at both the limbic and corticothalamic circuits sites. While in ANT stimulation or lesioning-group, there was significant reduction in LCGU at the corticothalamic circuit sites, but not so considerable decrease at the limbic structures.

Conclusion: ANT electrical stimulation and lesioning in the focal limbic seizure model were effective on convulsive seizures and secondary generalization, specifically with respect to the severity of these seizures.