Calcium-dependent changes of paired-pulse modulation at single GABAergic synapses.

Whole-cell patch-clamp and local electrical stimulation were used for measuring of monosynaptic GABAergic currents from rat hippocampal neurons in culture. Under control conditions (normal extracellular calcium, 2 mM) paired-pulse depression with 150 ms interpulse interval was observed. The mean current amplitude for both 1st and 2nd IPSCs displayed bell-shaped dependency from the stimulus amplitude.