Influence of cerebro-spinal fluid of picrotoxin kindled rats on seizure susceptibility and locomotor activity of recipients.

Repeated picrotoxin administration (ip) in subthreshold doses in rats resulted in kindling of generalized seizures. Decrease of locomotor activity in kindled rats occurred in interictal periods. Intra-cerebroventricular microinjection to intact recipients of cerebrospinal fluid (CSF) of kindled but not intact rats or those after acute picrotoxin-induced convulsions, induced a decrease of locomotor activity and severity of acute picrotoxin induced seizures. These effects of CSF were blocked by naloxone pretreatment and were absent after injection of CSF to which protease inhibitors were not added. It is concluded that the release of endogenous opioid peptide substance(s) takes place in CSF of kindled animals which cause the interictal decrease of locomotor activity and may play the role of endogenous anticonvulsive factors controlling epileptic activity induction.

Antiepileptic effects of cerebellar nucleus dentatus electrical stimulation under different conditions of brain epileptisation.

It was shown in acute experiments on cats that high frequency (100-300 Hz) electrical stimulation of dentate nucleus led to the solitary epileptic foci of relatively weak intensity suppression and at the same time caused the activation of stronger focal epileptic activity. Electrical stimulation of nucleus dentatus suppressed the epileptic activity of grand mal type and increased seizures in rats with petit mal form of epileptogenesis which was formed in rats during pentylenetatiozol kindling. It was concluded that there is a relation between the antiepileptic effects of nucleus dentatus irritation and intensity as well as the form of epileptic activity induced experimentally.