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. 2012 Dec 12;32(50):18215–18226. doi: 10.1523/JNEUROSCI.2327-12.2012

Figure 6.

Figure 6.

GluK1 subunit-containing KAR antagonists attenuate excitatory synaptic transmission and AP firing in a subset of sRad interneurons. All interneurons are recorded in the presence of d-AP5 (50 μm) plus L-689,560 (5 μm) and CGP 55845 (10 μm) to block NMDAR and GABABR-mediated components of synaptic transmission, respectively. A, Electrophysiological properties of sRad interneurons at the resting membrane potential. A single example of the voltage response of a sRad interneuron to depolarizing and hyperpolarizing current steps (±20 pA; 500 ms) recorded at its resting membrane potential (−58 mV) used to monitor intrinsic excitability and input resistance, respectively, together with pooled data (n = 21) of initial and final AP firing frequency during the depolarizing step (note some spike frequency adaptation), resting membrane potential, and input resistance. B, C, A single example (B) to illustrate the effect of LY382884 (dark gray) on intrinsic excitability, amplitude of low-frequency evoked EPSPs (closed circles) with stimulation adjusted such that AP firing occurs in some trials (open circles; AP amplitude; modified scale for ordinate on right y-axis; light gray, a single example of a baseline evoked response generating an AP is superimposed onto EPSP) and (C) interspersed TBS stimulation. D, Biocytin-filled sRad interneuron with KAR-mediated EPSP. E, Scatterplot to compare the effect of either ACET (circles) or LY382884 (triangles) on the relative change in EPSP amplitude and AP success rate. Interneurons were separated into two groups based solely on whether KAR antagonism depressed EPSP amplitude by >10% (filled) or not (open) (with this threshold illustrated by the vertical dotted line). F, Effect of KAR antagonism on both subpopulations of sRad interneurons comparing intrinsic excitability (total number of APs/s during a depolarizing step; 500 ms) and the following properties arising from evoked stimulation: relative EPSP amplitude, AP success rate for single shocks, and the total number of APs during a TBS train. sPyr, stratum pyramidale; sRad, stratum radiatum; sLM, stratum lacunosum-moleculare; f, hippocampal fissure.