Intracerebral microdialysis in the study of limbic seizure mechanisms and antiepileptic drug action using freely moving rats

In vivo microdialysis has become a widely used tool to help elucidate the neurochemical alterations accompanying epilepsy, as well as the mechanisms of action of both old and new generation antiepileptic drugs. With the need of novel antiepileptic drugs for the high percentage of pharmacoresistant patients, microdialysis serves both as a drug delivery tool and/or sampling method which is often combined with other complementary neurotechniques in order to discover potential drug leads. An advantage microdialysis presents in epilepsy-related investigations is that seizures are focally evoked in conscious animals that have minimal restrictions on their movements and general behavior. This allows for the analysis of seizure behavior manifestations by visual scoring of seizure severity in combination with electrical activity monitoring via electrocorticography. In this chapter we will demonstrate how one can use microdialysis to identify and further investigate known and potential anticonvulsant drugs, in addition to the better understanding of seizure mechanisms. Major focus will be given towards the focal pilocarpine model of limbic seizures.