Temporal changes in neuronal dropout following inductions of lithium/pilocarpine seizures in the rat

Estimates of neuronal dropout for approximately 100 structures as defined b y Paxinos-Watson were completed for brains of male Wistar albino rats betwe en 1 and 50 days after status epilepticus was evoked by a single systemic i njection of lithium and pilocarpine. Sample estimates of neuronal loss were strongly correlated with direct measures of cell density. The most extensi ve immediate damage occurred within the substantia nigra reticulata, CAI fi eld of the hippocampus, the piriform cortex and the reuniens and paratenial nuclei of the thalamus. Neuronal dropout continued in many other structure s over a 50-day period. Structures that showed the greatest 2-deoxyglucose (2-DG) uptake during discrete seizures and waxing and waning seizures withi n the early stages of status epilepticus but the least 2-DG uptake at the t ime of late continuous spiking and fast spiking with pauses [Neuroscience 6 4 (1995) 1057, 1075] exhibited the most neuronal dropout. Relationships bet ween the delay of injection of acepromazine (which facilitated survival) an d the amount of damage suggested that the sourer of the process that result s in permanent brain damage may originate within the region of the piriform cortices and its subcortices. (C) 2000 Elsevier Science B.V. All rights re served.