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Cortical Na+,K+-ATPase of immature rats following bicuculline-induced seizures
1Institute of Physiology, Czechoslovak Academy of Sciences, Prague.
Insights
Seizures induced by bicuculline did not affect sodium-potassium adenosine triphosphatase (Na+,K+-ATPase) activity in developing rat brains. Enzyme activity increased with age but remained unchanged by seizure activity under optimal in vitro conditions.
Area of Science:
- Neuroscience
- Biochemistry
- Developmental Biology
Background:
- Sodium-potassium adenosine triphosphatase (Na+,K+-ATPase) is crucial for neuronal function.
- Understanding its activity during development and under pathological conditions like seizures is important.
Purpose of the Study:
- To investigate the impact of bicuculline-induced seizures on Na+,K+-ATPase activity in the developing rat cerebral cortex.
- To examine age-dependent changes in enzyme activity.
Main Methods:
- Cerebral cortex homogenates from 7-, 12-, and 18-day-old rats were used.
- Seizures were induced via systemic bicuculline administration.
- Na+,K+-ATPase activity was measured in vitro under varying potassium concentrations.
Main Results:
- Na+,K+-ATPase activity increased with postnatal development in control rats.
- Seizure activity did not significantly alter enzyme activity when measured under optimal in vitro conditions.
- Potassium activation curves for Na+,K+-ATPase were similar across all age groups and unaffected by seizures.
Conclusions:
- Postnatal development enhances Na+,K+-ATPase activity in the rat cerebral cortex.
- Bicuculline-induced seizures do not significantly impact Na+,K+-ATPase activity in this model.
- The enzyme's kinetic properties remain consistent during development and seizure activity.
Abstract:
The Na+,K+-ATPase activity was investigated in cerebral cortex homogenates of 7-, 12- and 18-day-old rats in which seizures were induced by systemic (i.p.) administration of bicuculline. Na+,K+-ATPase activities in control animals increased during postnatal development, but they were not significantly influenced by seizure activity when determined under optimal conditions in vitro. Although the ratio of neuronal vs. non-neuronal cells in cortical samples of 7-, 12- and 18-day-old rats was different, there was a remarkable similarity in the activation curves for K+, obtained for Na+,K+-ATPase of all age groups under normal conditions; 50% of enzyme activities were attained at 1 mmol.l-1 K+ and the maximal activities were found around 10 mmol.l-1 K+. The activation curves for K+ in rats with bicuculline-induced seizures were not significantly different from those of the controls.