Does seizure activity produce Purkinje cell loss?

Eight Wistar rats were exposed to 140 electroconvulsive seizures over 50 days. Ten rats served as controls. The density of Purkinje cells in cerebellum ranged from 15.3 to 18.5/mm in the treated rats and from 15.2 to 19.1/mm in the controls. No Purkinje cell loss was disclosed in the rats subjected to electroconvulsive seizures. Twenty-five Mongolian gerbils of the seizure-susceptible strain were selected according to seizure score with five animals in each group. Five Mongolian gerbils of a seizure-resistant strain served as controls. The density of the Purkinje cells ranged from 21.4 to 29.8/mm in the seizure-susceptible animals and from 27.6 to 31.5/mm in the controls, with a lower density in the gerbils with seizures compared with the controls (p less than 0.05). There was no relation to type or number of seizures. Eight gerbils of the seizure-susceptible strain were included as a supplementary group, to disclose any possible genetic trait as an explanation of the lower Purkinje cell density. The Purkinje cell density in these animals ranged from 24.8 to 30.9/mm and did not differ from the density in the seizure-resistant gerbils. Thus the lower density of Purkinje cells in the seizure-susceptible Mongolian gerbils is a result of seizure activity. The excessive epileptic input with stimulation of the glutamatergic innervation of the Purkinje cells resulting in a persistent elevated gamma-aminobutyric acid (GABA) tone may explain the damage to the Purkinje cells in the gerbils and the loss of Purkinje cells found in patients with severe epilepsy.