Anticonvulsant effect of Annona diversifolia Saff. and palmitone on penicillin-induced convulsive activity. A behavioral and EEG study in rats.

PURPOSE: To evaluate hypnotic and anticonvulsant activities of Annona diversifolia Saff. and palmitone by using behavior and electroencephalographic (EEG) analysis in an experimental model of focal seizures in rats.
METHODS: For hypnotic assessment, EEG analysis of polysomnographic slow-wave sleep (SWS) and rapid eye movement (REM) sleep for a 1 h period were performed after vehicle, A. diversifolia extract or palmitone, administration. For anticonvulsant effect, 60 minutes after treatments, EEG and behavior were analyzed during penicillin-induced seizures. Latency to the onset of the first paroxystic spike, first seizure and frequency, as well as seizure severity using Racine's scale, were determined.
RESULTS: Palmitone, but not A. diversifolia extract, produced a delay in the latency to the SWS phase. In addition, both palmitone and extract decreased SWS duration and accumulated REM sleep phase. With regard to the seizures, both the extract and palmitone increased the latency to the onset of spikes and seizures, but also decreased the duration of penicillin-induced seizures. This reduction in the EEG recordings was associated with an attenuation in the severity of behavioral seizures.
CONCLUSIONS: A. diversifolia and palmitone did not produce a sedative-hypnotic effect although both of them were effective in reducing the severity of behavioral and EEG seizures induced by penicillin in rats, suggesting that the diminution in the paroxystic activity by A. diversifolia is likely produced by palmitone through GABAergic neurotransmission. This study justifies and reinforces the traditional use of this plant in epilepsy.