Anticonvulsants in epileptic fowl

Area of Science:

• Neuroscience
• Genetics
• Pharmacology

Background:

• Epileptic fowl possess an autosomal recessive trait leading to high seizure susceptibility.
• Seizures in these fowl can be spontaneously triggered or induced by photic stimulation or hyperthermia.
• Abnormal inter-ictal electroencephalogram (EEG) activity is observed in epileptic fowl.

Purpose of the Study:

• To evaluate the utility of epileptic fowl as an animal model for human epilepsy.
• To assess the anticonvulsant effects of various drugs in this model.
• To investigate the potential of this model for studying drugs targeting GABAergic transmission.

Main Methods:

• Evoking seizures using photic stimulation and hyperthermia.
• Administering drugs such as phenobarbital, primidone, phenytoin, valproic acid, carbamazepine, benzodiazepines, ethosuximide, and trimethadione.
• Testing the anticonvulsant activity of gamma-aminobutyric acid (GABA) and related compounds.

Main Results:

• Phenobarbital, primidone, phenytoin, valproic acid, carbamazepine, and benzodiazepines reduced seizure susceptibility in response to photic stimulation.
• Ethosuximide was ineffective, while trimethadione showed anticonvulsant activity.
• Phenobarbital, but not phenytoin or valproate, reduced hyperthermia-induced seizures.
• GABA, amino-oxyacetic acid (AOAA), and THPO demonstrated anticonvulsant effects against photic-induced seizures.

Conclusions:

• Epileptic fowl serve as a valuable model for generalized and focal cortical tonic-clonic epilepsies.
• The model shows relative specificity, being less responsive to ethosuximide but responsive to trimethadione.
• This model is particularly useful for studying anticonvulsants that enhance GABAergic transmission.