Influences of pituitary-adrenal hormones on kindling

The kindling process represents a progressively augmenting electrical and behavioral response to brain stimulation, that has been proposed as a model for the development of epileptogenesis. The first experiment examined the effects of hypophysectomy on the kindling process. The effects of hypophysectomy were found to be dependent on the number of days between hypophysectomy and the beginning of kindling. The kindling rate was slowed, compared to intact controls, when hypophysectomy was performed less than 2 weeks prior to the first kindling stimulation. However, if more than 4 weeks and passed since hypophysectomy, the kindling rate was faster than that of intact controls. The second experiment tested the influence of systemic administration of cortisone (10 mg/animal), upon kindling of control and hypophysectomized animals. Cortisone was found to reverse the kindling deficit of hypophysectomized animals at less than 2 weeks and to slow kindling of intact controls, but to have no effect on hypophysectomized animals at more than 4 weeks (at this dose). These results are interpreted as indicating that pituitary-adrenal hormones have profound influences on the kindling process, but it is unclear whether the influence is upon brain excitability or more directly upon modification of synaptic function.