Benzodiazepines modulate calcium spikes in young and adult hippocampal cells.

GABAA receptor-independent effects of benzodiazepine receptor (BZ-R) agonists on calcium and barium spikes were recorded intracellularly in the presence of bicuculline from CA3 hippocampal cells of young and adult rats. Zolpidem (omega 1 BZ-R agonist), had no effects in young animals but decreased calcium and barium spikes and barium currents in adults. Midazolam (omega 1 and omega 2 BZ-R agonist) increased barium spikes in both young and adult animals. The effects on calcium spikes were more complex since a decrease was sometimes preceded by an increase. Thus, in adults zolpidem acting on omega 1 BZ-R reduced calcium influx while in young rats midazolam acting on omega 2 BZ-R increased barium influx. This modulation of calcium spikes by benzodiazepines could be relevant of calcium spikes by benzodiazepines could be relevant because of the developmental role played by calcium dependent processes.