Epilepsy is the most common serious neurological condition and approximately 50 million people worldwide are affected. Epilepsies are characterized by spontaneous recurrent seizures, caused by focal or generalized paroxysmal changes in neurological functions triggered by abnormal electrical activity in the cortex. Because it involves hyperexcitable neurons, a basic assumption links the pathogenesis of epilepsy and the generation of synchronized neuronal activity with an imbalance between inhibitory [gamma-aminobutyric acid (GABA)-mediated] and excitatory (glutamate-mediated) neurotransmission, in favor of the latter (PMID:19722008).
Understanding the pathophysiogenesis of temporal lobe epilepsy (TLE) largely rests on the use of models of status epilepticus (SE), as in the case of the pilocarpine model. The main features of TLE are: (i) epileptic foci in the limbic system; (ii) an "initial precipitating injury"; (iii) the so-called "latent period"; and (iv) the presence of hippocampal sclerosis leading to reorganization of neuronal networks. Many of these characteristics can be reproduced in rodents by systemic injection of pilocarpine; in this animal model, SE is followed by a latent period and later by the appearance of spontaneous recurrent seizures (SRSs). These processes are, however, influenced by experimental conditions such as rodent species, strain, gender, age, doses and routes of pilocarpine administration, as well as combinations with other drugs administered before and/or after SE (PMID:18550176).
Therefore, the pilocarpine model of epilepsy is a valuable tool not only to study the pathogenesis of temporal lobe epilepsy in human condition, but also to evaluate potential antiepileptogenic drugs (PMID:19722008).