Lithium/Pilocarpine Status Epilepticus-Induced Neuropathology of Piriform Cortex and Adjoining Structures in Rats is Age-Dependent

R. DRUGA^1,2, H. KUBOVÁ¹, L. SUCHOMELOVÁ¹, R. HAUGVICOVÁ¹

Received March 8, 2002
Accepted May 30, 2002

Summary
Distribution of LiCl/pilocarpine status epilepticus-induced neuronal damage was studied in the piriform cortex and in adjoining structures in 12-day-old, 25-day-old and adult rats. No distinct structural and neuronal alterations were detected in the basal telencephalon in 12-day-old rats surviving status epilepticus (SE) for one week or two months. In 25-day-old rats a decrease in Nissl staining was evident. There was also cell loss and gliosis in the caudal 2/3 of the piriform cortex, in the superficial amygdaloid nuclei, in the dorsal and ventral endopiriform nucleus and in the rostrolateral part of the entorhinal cortical area. In adult animals, the topography of neuropathological changes in the basal telencephalon was comparable to those in 25-day-old rats. The damage in the caudal 2/3 or caudal half of the piriform cortex in adult rats with survival times one week or two months was characterized by a marked loss of neurons and striking glial infiltration. The thickness of the piriform cortex and superficial amygdaloid nuclei was significantly reduced. In 25-day-old and in adult animals the sublayer IIb and layer III of the piriform cortex was more affected, while sublayer IIa was less damaged. Parvalbumin (PV) immunocytochemistry revealed a significant decrease in the number of PV-immunoreactive neurons in the rostral piriform cortex and in the dorsal claustrum in animals surviving for two months.

Key words
Epilepsy • Piriform cortex • Endopiriform nucleus • Basal telencephalon • Pilocarpine • Parvalbumin

Reprint requests
R. Druga, M.D., D.Sc., Institute of Physiology, Academy of Sciences of the Czech Republic, Vídeňská 1083,
CZ-142 20 Prague 4, Czech Republic. E-mail: Druga@biomed.cas.cz