Behavioral alterations in the pilocarpine model of temporal lobe epilepsy in mice

Exp Neurol. 2007 Oct;207(2):329-49. doi: 10.1016/j.expneurol.2007.06.021. Epub 2007 Jul 12.


Psychiatric disorders frequently occur in patients with epilepsy, but the relationship between epilepsy and psychopathology is poorly understood. Frequent comorbidities in epilepsy patients comprise major depression, anxiety disorders, psychosis and cognitive dysfunction. Animal models of epilepsy, such as the pilocarpine model of acquired epilepsy, are useful to study the relationship between epilepsy and behavioral dysfunctions. However, despite the advantages of mice in studying the genetic underpinning of behavioral alterations in epilepsy, mice have only rarely been used to characterize behavioral correlates of epilepsy. This prompted us to study the behavioral and cognitive alterations developing in NMRI mice in the pilocarpine model of epilepsy, using an anxiety test battery as well as tests for depression, drug-induced psychosis, spatial memory, and motor functions. In order to ensure the occurrence of status epilepticus (SE) and decrease mortality, individual dosing of pilocarpine was performed by ramping up the dose until onset of SE. This protocol was used for studying the consequences of SE, i.e. hippocampal damage, incidence of epilepsy with spontaneous recurrent seizures, and behavioral alterations. SE was terminated by diazepam after either 60, 90 or 120 min. All mice that survived SE developed epilepsy, but the severity of hippocampal damage varied depending on SE length. In all anxiety tests, except the elevated plus maze test, epileptic mice exhibited significant increases of anxiety-related behavior. Surprisingly, a decrease in depression-like behavior was observed in the forced swimming and tail suspension tests. Furthermore, epileptic mice were less sensitive than controls to most of the behavioral effects induced by MK-801 (dizocilpine). Learning and memory were impaired in epileptic mice irrespective of SE duration. Thus, the pilocarpine-treated mice seem to reflect several of the behavioral and cognitive disturbances that are associated with epilepsy in humans. This makes these animals an ideal model to study the neurobiological mechanisms underlying the association between epilepsy and psychopathology.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analysis of Variance
  • Animals
  • Anxiety / etiology
  • Behavior, Animal / drug effects*
  • Disease Models, Animal
  • Dizocilpine Maleate / pharmacology
  • Dose-Response Relationship, Drug
  • Drug Administration Routes
  • Drug Interactions
  • Epilepsy, Temporal Lobe / chemically induced*
  • Epilepsy, Temporal Lobe / drug therapy
  • Epilepsy, Temporal Lobe / pathology
  • Epilepsy, Temporal Lobe / physiopathology*
  • Excitatory Amino Acid Antagonists / pharmacology
  • Exploratory Behavior / drug effects
  • Female
  • Hindlimb Suspension / methods
  • Hippocampus / drug effects
  • Hippocampus / pathology
  • Maze Learning / drug effects
  • Mice
  • Neuronal Plasticity / drug effects
  • Pilocarpine*
  • Psychomotor Performance / drug effects
  • Time Factors


  • Excitatory Amino Acid Antagonists
  • Pilocarpine
  • Dizocilpine Maleate