Bilateral anterior thalamic nucleus lesions and high-frequency stimulation are protective against pilocarpine-induced seizures and status epilepticus.
OBJECTIVE
The thalamus is thought to play an important role in secondary generalization of seizures. The aim of the present study was to investigate the influence of anterior thalamic nucleus lesions and high-frequency stimulation in the pilocarpine model of secondarily generalized seizures in rats.


METHODS
Adult Wistar rats underwent unilateral (n = 7) or bilateral anterior nucleus thalamotomies (n = 10), or unilateral (n = 4) or bilateral (n = 9) anterior thalamic nucleus stimulation through implanted electrodes. Control animals (n = 9) received bilateral implants but no stimulation. Seven days after these procedures, animals were provided pilocarpine (320 mg/kg intraperitoneally) to induce seizures and status epilepticus (SE). Electrographic recordings from hippocampal and cortical electrodes were evaluated, and ictal behavior was assessed.


RESULTS
In the control group, 67% of the animals developed SE 15.3 +/- 8.8 minutes after pilocarpine administration. Neither unilateral anterior nucleus lesions nor stimulation significantly reduced the propensity or latency for developing seizures and SE. Bilateral thalamic stimulation did not prevent SE (observed in 56% of the animals), but it significantly prolonged the latency to its development (48.4 +/- 17.7 min, P = 0.02). Strikingly, no animal with bilateral anterior nucleus thalamotomies developed seizures or SE with pilocarpine.


CONCLUSIONS
Bilateral anterior thalamic nuclear complex stimulation and thalamotomies were protective against SE induced by pilocarpine.
Hamani
Clement
C
Division of Neurosurgery, University of Toronto, Toronto, Ontario, Canada.
Ewerton
Flavio I S
FI
Bonilha
Saulo M
SM
Ballester
Gerson
G
Mello
Luiz E A M
LE
Lozano
Andres M
AM
D000818:Animals; D020643:Anterior Thalamic Nuclei / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D004195:Disease Models, Animal; D004599:Electric Stimulation Therapy; D004569:Electroencephalography; D008297:Male; D018721:Muscarinic Agonists; D010862:Pilocarpine; D051381:Rats; D017208:Rats, Wistar; D012640:Seizures / Q000139:chemically induced / Q000503:physiopathology / Q000517:prevention & control*; D013226:Status Epilepticus / Q000139:chemically induced / Q000503:physiopathology / Q000517:prevention & control*
D018721:Muscarinic Agonists; D010862:Pilocarpine