Figure 4.

GABA_B autoreceptors do not contribute to PPD of unitary IPSPs

Aa, pairs of IPSPs generated by a stratum oriens interneuron in a postsynaptic pyramidal cell. The selective GABA_B receptor antagonist CGP52432 (2 μm, dashed trace) had no significant effect on either the amplitude or the PPD of the IPSP. Average of 30 consecutive responses. Ab, summary data from 9 independent cell pairs with the interneuron located in either stratum oriens or stratum radiatum. Ba, similar experiment using extracellular synaptic stimulation. The intensity of stimulation was set so that IPSP amplitude was similar to that in the above experiments. CGP52432 did not affect the amplitude of evoked IPSPs but significantly reduced PPD at both 50 and 400 ms interstimulus intervals. Bb, summary data from 10 independent experiments.