Chemical Models in Typical Absence Epilepsy Studies: A Review on Advantages and Disadvantages

There are several substances for induced absence seizure that used locally or systemically based on the aim of the study. Systemic Penicillin, low-dose pentylentetrazole (L-PTZ), the 4,5,6,7 tetrahydroisoxazolo [4,5, -c] pyridine-3-ol (THIP) model, and gamma-Hydroxybutyrate(GHB) model are the most common models for typical absence epilepsy as well as AY-9944 and methylazzoxymethanol acetate (MAM)-AY-9944 models administrate for induced atypical absence seizures. Local Administration of some antibiotics such as cephalosporinand penicillin onto the cortex or systemically at high doses can induce seizure in cats and rodents. Penicillin has limited effect in rodents rather than cats. Because of unstable penetration of penicillin through the bloodbrain barrier into the brain, produces multifocal spikeswith only occasional bursts of bilaterally synchronous spike and wave discharges (SWDs) associated with a decrease in attention. In fact, seizures initiated through parenteral penicillin have minor similarity to clinical absence seizures in rats. PTZ is the most commonly usedepileptic induced agent for systemic convulsive epilepsy. The extensive use of PTZ in different types of epilepsy is caused this model as an identifier of anticonvulsants and pro-convulsants. GHB is a GABA metabolite substance that produces naturally in the mammalian brain. After IP administration of GHB, electrographic and behavioral events occurs, similar to generalized absence seizures in the cats, rats, and monkeys. GBL a prodrug of GHB, increases the reproducibility and predictability of the GHB model of absence seizures. GBL is more commonusage because of the consistency and rapidity of onset of its effect and has been shown to produce exactly the same EEG and behavioral effect as that of GHB. This model is very appropriate experimental model for the study of the mechanisms of bilaterally synchronous SWD production and screen for anti-absence activity of antiepileptic drugs in generalized absence seizures. THIP is a GABA agonist that induces bilaterally synchronous SWDs in rats. THIP is a selective GABA agonist for the extra synaptic Deltasubunits of GABAA receptors. This model is quantitated similar to GHB model.