Fig. 7. Simultaneous recordings of IPSCs and [Cl−]i during synaptic stimulation.
(a) Current (upper trace), simultaneous fluorescence (ΔF/F0, center traces) and Cl− signals (bottom trace) from the soma of a CLM1 hippocampal CA1 pyramidal cell (P20). Each trace represents an average of 3 individual responses. IPSCs are shown on an expanded time scale to allow resolution of individual responses. Stimulus artifacts were blanked for clarity. The arrows (Stim) in a and b depict the time of electrical stimulation (1 s, 23 Hz) at the border of stratum radiatum and lacunosum-moleculare. Fluorescence imaging in this and all subsequent figures was done with a wide-field microscope.
(b) Both IPSC and Cl− transient (left) were blocked by SR (center) and partially recovered after washout (right). SR was applied at 10 μM.
(c) Correlation of changes in [Cl−]i and the numbers of stimuli in trains. Each point and error bar represents average and SEM, respectively, from 6 cells. A shaded region denotes RMS value of basal fluctuation in [Cl−]i in single trials.
(d) Correlation of changes in [Cl−]i and Cl− influx. 3–11 responses from 14 cells were binned.