Fig. 2: D-serine controls threshold and amplitude of dendritic spikes evoked by glutamate uncaging.

a Two-photon glutamate uncaging. Example of a CA1 pyramidal cell filled with Alexa Fluor 594 (100 µM, left panel, scale bar 40 µm). Right panel: investigated dendrite (scale bar 10 µm). b Examples of uncaging-evoked somatic EPSPs (uEPSP, scale bars 0.5 mV and 20 ms, average uEPSP in yellow). c Left panel: comparison of the measured amplitudes of somatic responses evoked by quasi-simultaneous stimulation of a set of spines with the sum of single-spine uEPSPs (black: no spikes, yellow: spikes detected). Right top panel: individual responses corresponding to the left panel (scale bars 2 mV and 20 ms). Right bottom panel: dV/dt of traces above (scale bars 1 mV/ms and 5 ms). d Left panel: thresholds of dendritic spikes were significantly increased with blocked NMDARs (D-APV, 40 µM, red, 4.59 ± 0.37 mV vs. 5.34 ± 0.57 mV, n = 6, p = 0.039). Middle panel: NMDAR inhibition decreased the slow component of the dendritic spike (6.70 ± 0.86 mV vs. 5.32 ± 0.78 mV, n = 6, p = 0.0097). Right panels: sample traces as in Fig. 1d (scale bars 2 mV and 50 ms, inset dV/dt scale bars 1 mV/ms and 10 ms). e Application of of D-serine (10 µM, blue) decreased the dendritic spike threshold (left panel, 7.09 ± 0.94 mV vs. 5.82 ± 0.75 mV, n = 6, p = 0.049) and increased its slow component (middle panel, 9.33 ± 1.07 mV vs. 11.29 ± 1.40 mV, n = 6, p = 0.045). Right panels: example traces as in Fig. 1e (scale bars 2 mV and 20 ms, inset dV/dt scale bars 1 mV/ms and 10 ms). Two-sided paired Student’s t tests throughout. Data are expressed and displayed as mean ± s.e.m. Source data are provided as a Source Data file.