Figure 5
Changes in extracellular Ca2+ concentration sensitivity of inhibitory synapses in Scn1a+/− neurons. (a) Inhibitory postsynaptic current (IPSC) amplitudes recorded in different extracellular [Ca2+]o (0.5, 1, 2, 4, 8 mM) with 1 mM Mg2+ held constant in wild-type (WT) and Scn1a+/− neurons (WT: n = 35, Scn1a+/−: n = 36/N = 9 cultures). (b) Dose–response curves and Hill fits for normalized IPSC amplitudes, recorded in different extracellular [Ca2+]o (0.5, 1, 2, 4, 8 mM) with 1 mM Mg2+, held constant in WT and Scn1a+/− neurons. IPSC amplitudes were normalized to the IPSC amplitude at 8 mM [Ca2+]o. Original data were obtained from the same cells as in (a). (c) Representative traces of evoked excitatory postsynaptic currents (EPSCs) recorded at 2 mM [Ca2+]o (black line) and 8 mM [Ca2+]o (red line) from neurons of either WT or Scn1a+/− mice. Depolarization artifacts caused by the generated action currents have been removed for clarity of presentation. (d) Average magnification of evoked EPSCs at 8 mM [Ca2+]o based on EPSC amplitudes at 2 mM [Ca2+]o in neurons of WT or Scn1a+/− mice (WT: 1.45 ± 0.07, n = 62, Scn1a+/−: 1.48 ± 0.07, n = 64/N = 11 cultures). (e) Representative traces of evoked IPSCs recorded at 2 mM [Ca2+]o (black line) and 8 mM [Ca2+]o (red line) from neurons of either WT or Scn1a+/− mice. Depolarization artifacts caused by the generated action currents have been removed for clarity of presentation. (f) Average magnification of the evoked IPSCs at 8 mM [Ca2+]o based on IPSC amplitudes at 2 mM [Ca2+]o in neurons of WT or Scn1a+/− mice (WT: 1.36 ± 0.09 mM, n = 35, Scn1a+/−: 1.02 ± 0.04 mM, n = 36/N = 9 cultures, ***p < 0.001).
