The influence of hippocampal kindling on sleep organization in cats. Effects of alpha-methylparatyrosine.

Abstract The effects of daily electrical stimulation of ventral hippocampus (hippocampal kindling) on the sleep-waking cycle wer studied in the cat. Hippocampal kindling developed in 61 days and 4 stages according to progressive development of EEG and behavioral seizures and culminated in generalized convulsions. The ‘all or none’ response of Goddard was found once generalized seizures appeared. The influence of the hippocampal kindling effect on the sleep-waking cycle was investigated in kindling and kindled cats. Paradoxical sleep (PS) decreased from stage 2 to stage 4. This diminution persisted even if stimulation was stopped. No significant modifications of waking (W) and slow wave sleep (SWS) occured. A peculiar facilitation of interictal discharges by SWS was noticed. In contrast, waking and PS inhibited them. The influence of the modification of the sleep-waking cycle induced by alpha- methylparatyrosine (AMPT) known as an inhibitor of catecholamine (CA) synthesis was investigated in hippocampal kindling. Two principal results were found: (1) a PS increase during the 6 h following AMPT injection; (2) a lack or a delay of kindling in two animals which showed an increase of PS after AMPT injections. These results are discussed according to the modifications of both the sleep- waking cycle and the brain catecholamine levels secondary to AMPT treatment.