The effect of electrical stimulation and lesioning of the anterior thalamic nucleus on kainic acid-induced focal cortical seizure status in rats.
OBJECTIVE
The present study aimed to clarify the effect of electrical stimulation and lesioning of the anterior nucleus of the thalamus (ANT) on kainic acid (KA)-induced focal cortical seizures in a rat model. To address the mechanism underlying these anticonvulsant actions, cerebral glucose metabolism after ANT electrical stimulation and lesioning was also examined.


METHODS
Wistar rats were divided into five major groups: control (n = 9), unilateral (n = 9), and bilateral (n = 9) ANT electrical stimulation, and unilateral (n = 9) and bilateral (n = 9) ANT lesioning. After KA injection, average clinical-seizure frequencies in each group were measured. Electrical stimulation of ANT was introduced after induction of seizure status epilepticus. Stimulation was on for 30 min and off for 30 min per 60-min cycle. Local cerebral glucose utilization (LCGU) was also measured by using [(14)C] 2-deoxyglucose autoradiography in three groups of rats: control (n = 7), bilateral ANT stimulation (n = 7), and bilateral ANT lesioning (n = 7).


RESULTS
Unilateral ANT electrical stimulation and lesioning significantly reduced clinical seizure frequency, compared with control animals. Strikingly, no animals treated with bilateral ANT procedures demonstrated any clinical seizure. LCGU was markedly increased in the sensorimotor cortex, striatum, thalamus, mammillary body, and midbrain tegmentum of control group rats after KA injection, but no increase in LCGU was noted in rats treated with bilateral ANT lesioning or stimulation.


CONCLUSIONS
The electrical stimulation and lesioning of ANT suppressed focal cortical clinical seizures induced by KA injection. Additionally, an analysis of cerebral metabolic changes indicated that these procedures might suppress the function as amplifier and synchronizer of seizure activity.
Takebayashi
Seiji
S
Department of Neurosurgery, Asahikawa Medical College, Asahikawa, Japan. tikurin@asahikawa-med.ac.jp
Hashizume
Kiyotaka
K
Tanaka
Tatsuya
T
Hodozuka
Akira
A
D000818:Animals; D020643:Anterior Thalamic Nuclei / Q000473:pathology* / Q000503:physiopathology*; D001345:Autoradiography; D001921:Brain / Q000378:metabolism; D002250:Carbon Radioisotopes / Q000378:metabolism; D003847:Deoxyglucose / Q000378:metabolism; D004195:Disease Models, Animal; D004558:Electric Stimulation / Q000379:methods*; D004599:Electric Stimulation Therapy; D004567:Electrodes, Implanted; D004569:Electroencephalography; D004828:Epilepsies, Partial / Q000139:chemically induced / Q000503:physiopathology* / Q000517:prevention & control*; D007839:Functional Laterality / Q000502:physiology; D005947:Glucose / Q000378:metabolism; D007608:Kainic Acid; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013226:Status Epilepticus / Q000139:chemically induced / Q000378:metabolism / Q000517:prevention & control; D013238:Stereotaxic Techniques; D014018:Tissue Distribution
D002250:Carbon Radioisotopes; D003847:Deoxyglucose; D005947:Glucose; D007608:Kainic Acid