Calcium transport was assessed within synaptic terminals isolated from cerebral cortices of rats which experienced one maximal electroshock (ES) convulsion daily. No significant change in calcium content [(Ca(i))] of synaptosomes was present after 2 consecutive days of maximal convulsions. After 4 and 6 days of maximal seizures, (Ca(i)) rose 20% and 37%, respectively. 45Ca2+ influx within synaptosomes in vitro increased after 6 days of ES convulsions (1.94 ± 0.4 μmol/g protein/min in ES convulsions versus 1.54 ± .03 μmol/g protein/min in controls). The higher rate of 45Ca2+ influx in convulsed animals was accounted for by elevated internal sodium [(Na(i))] values. Maximal 45Ca2+ efflux decreased after ES convulsions (0.48 μmol/g protein/min in ES convulsions versus 0.8 μmol/g protein/min in controls). The slower rate of 45Ca2+ efflux after convulsions was also accounted for by elevated (Na(i)). Our results suggest that (Ca(i)) increased within synapses after in vivo ES convulsions secondary to a primary ionic event, namely, elevated (Na(i)).
|Original language||English (US)|
|Number of pages||9|
|Journal||Journal of neurochemistry|
|State||Published - May 1980|
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience