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Proconvulsant effect of aminophylline on cortical epileptic afterdischarges varies during ontogeny
1Institute of Physiology, Academy of Sciences of the Czech Republic, Vídeñská 1083, CZ-142 20, Prague, Czech Republic.
Insights
Aminophylline significantly increases seizure activity in young rats, particularly promoting a transition to more severe limbic seizures. This proconvulsant effect diminishes with age, highlighting developmental changes in brain response.
Area of Science:
- Neuroscience
- Developmental Neuroscience
- Epilepsy Research
Background:
- Aminophylline is a methylxanthine drug with known central nervous system effects.
- Epileptic afterdischarges (ADs) are a model for studying seizure phenomena.
- Postnatal development significantly influences neuronal excitability and drug responses.
Purpose of the Study:
- To investigate the effect of aminophylline on experimentally induced epileptic afterdischarges (ADs) in rat pups of different postnatal ages.
- To characterize age-dependent changes in aminophylline's proconvulsant activity.
- To examine the transition of seizure types and their duration under aminophylline treatment.
Main Methods:
- Rhythmic electrical stimulation of the sensorimotor cortex in rat pups aged 12, 18, and 25 days.
- Intraperitoneal administration of aminophylline at doses of 50 and/or 100 mg/kg.
- Observation and quantification of epileptic afterdischarge (AD) types (spike-and-wave vs. limbic) and durations.
- Comparison of AD characteristics between aminophylline-treated groups and age-matched controls.
Main Results:
- Aminophylline exhibited a more pronounced proconvulsant effect in 12- and 18-day-old rats compared to 25-day-old rats.
- In 12-day-old pups, aminophylline greatly increased the transition from spike-and-wave ADs to longer, limbic ADs.
- Eighteen-day-old rats showed less transition but experienced prolonged spike-and-wave ADs, sometimes leading to status epilepticus.
- In 25-day-old rats, aminophylline only caused transient prolongation of spike-and-wave ADs, with limbic transition occurring exceptionally.
Conclusions:
- Aminophylline's proconvulsant effect on cortical ADs is most significant in the youngest age group (12 days) and diminishes with postnatal development.
- The drug alters the pattern of seizure development, promoting a shift towards more severe limbic seizures in immature brains.
- These findings demonstrate a qualitative change in aminophylline's effect on seizure activity during postnatal development, with implications for understanding age-related epilepsy vulnerability.
Abstract:
Effect of aminophylline on epileptic afterdischarges (ADs) induced repeatedly by rhythmic electrical stimulation of sensorimotor cortical area was studied in rat pups 12, 18 and 25 days old. The proconvulsant effect of aminophylline (50 and/or 100 mg/kg i.p.) was more expressed in 12- and 18-day-old rats than in the oldest group. In 12-day-old rat pups there was an enormous increase of transition of the spike-and-wave type of ADs into the second, limbic type, a situation observed only exceptionally under control conditions. A prolongation of ADs was related to this transition (limbic ADs are always longer than spike-and-wave ones). Eighteen-day-old rats exhibit this transition less frequently but a marked prolongation of spike-and-wave ADs was recorded in a part of these animals forming a pattern of status lasting some tens of minutes. Aminophylline led only to a transient prolongation of spike-and-wave ADs in the oldest group. The transition into the limbic type of ADs was seen in this age group only exceptionally what is in contrast to age-matched controls in which this transition is common. The effect of aminophylline on cortical ADs which is most marked in the youngest group changes qualitatively during postnatal development.