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. 2013 Sep 30;592(Pt 1):87–102. doi: 10.1113/jphysiol.2013.261735

Figure 1. Patterns of synchronous responses evoked synaptically in hippocampal CA1 pyramidal cells and astrocytes.

Figure 1

A, sample picture of a stratum radiatum astrocyte patched with a pipette containing both dextran tetamethylrhodamine, a gap junction-impermeant dye used to localize the recorded cell (red, 0.1%), and 2-NBDG (green, 0.2%), diffusing to neighbouring gap junctional-coupled astrocytes. Scale bar, 20 μm. Inset, whole-cell current profile from a CA1 astrocyte evoked by 150 ms voltage steps in 20 mV increments (−200 to +40 mV); scale bar, 1.5 nA, 15 ms. B, scheme of the hippocampus illustrating the arrangement of the stimulating electrode, to activate the SCs, the patch pipette electrode (grey), to record astrocytic currents, and the neuronal recording electrode (extracellular or patch pipette) (black), to record either fEPSPs or EPSCs, EPSPs and action potentials (APs), evoked by SC stimulation in the hippocampal CA1 area. C, sample traces of an inward current (Im, black), recorded in voltage-clamp, and the concomitant membrane depolarization (Vm, grey), recorded in current-clamp, evoked in the same astrocyte by SC stimulation. Scale bar, 2.5 mV and 10 pA, 1 s. D, amplitude and kinetics of both signals (Im and Vm; n= 6). E, representative traces of simultaneous recordings of synaptically evoked currents in astrocytes (upper panel, grey) and neuronal fEPSPs (lower panel, black). Scale bar, 20 pA for astroglial current and 0.2 mV for fEPSPs, 25 ms. F, input–output curve illustrating the relationship between evoked presynaptic fibre volleys (input) and astroglial currents (ouput), recorded simultaneously (n= 6). G and I, representative traces of simultaneous recordings of synaptically evoked currents in astrocytes (left traces, grey) and evoked EPSCs (G) or EPSPs and APs (I) in single pyramidal neurons (right traces, black). Scale bars, 60 pA for astroglial current and 100 pA for EPSCs, 50 ms (G) and 60 pA for astroglial current and 20 mV for EPSPs and APs, 100 ms (I). H and J, the relationship between evoked astroglial currents and neuronal EPSCs (H) or APs (J), recorded simultaneously in dual whole cell recordings (n= 5).