Fig. 5
Reduced cytosolic Ca2+ increases induced by repetitive stimulation in hippocampal DG granule neurons of PS cDKO mice. a (Left) DIC image of DG granule neurons in an acute hippocampal slice in the course of whole-cell recording. (Right) Fluorescence image obtained from a soma of DG granule neurons loaded with 100 μM Fura 2 via a whole-cell patch pipette. Scale bars: 20 μm. b-d Electrophysiological characteristics of mature DG granule neurons: mean values for resting membrane potential (Control: −78.25 ± 0.94 mV; PS cDKO: −77.83 ± 0.41 mV), threshold currents for triggering of action potential (Control: 125.7 ± 12.3 pA; PS cDKO: 111.4 ± 11.9 pA) and input resistance (Control: 200.4 ± 16.5 MΩ; PS cDKO: 211.8 ± 13.4 MΩ). e Resting Ca2+ level (Control: 62.1 ± 4.1 nM; PS cDKO: 82.9 ± 7.4 nM) is not significantly different between control and PS cDKO mice. f The amplitude of ∆[Ca2+]i elicited by 10 repetitive stimulation (depolarizing pulses of 2 ms duration; from −80 to 0 mV) at 5, 10, 20 Hz is reduced in PS cDKO granule neurons. g Representative Ca2+ transients evoked by 10 repetitive stimulation at various frequencies (1, 5, 10, and 20 Hz). Scale bars: 2 s, 100 nM. All data represent means ± SEM (* p < 0.05, ** p < 0.01, NS: not significant; Student’s t-test). The values in parentheses indicate the number of neurons (left) and the number of mice (right) used in each experiment