The Pilocarpine Model of Mesial Temporal Lobe Epilepsy: Over One Decade Later, with More Rodent Species and New Investigative Approaches

Fundamental work on the mechanisms leading to focal epileptic discharges in mesial temporal
lobe epilepsy (MTLE) often rests on the use of rodent models in which an initial status epilepticus (SE) is induced by kainic acid or pilocarpine. In 2008 we reviewed how, following systemic
injection of pilocarpine, the main subsequent events are the initial SE, the latent period, and the
chronic epileptic state. Up to a decade ago, rats were most often employed and they were
frequently analysed only behaviorally. However, the use of transgenic mice has revealed novel
information regarding this animal model. Here, we review recent findings showing the existence
of specific neuronal events during both latent and chronic states, and how optogenetic activation
of specific cell populations modulate spontaneous seizures. We also address neuronal damage
induced by pilocarpine treatment, the role of neuroinflammation, and the influence of circadian
and estrous cycles. Updating these findings leads us to propose that the rodent pilocarpine model
continues to represent a valuable tool for identifying the basic pathophysiology of MTLE.