FIGURE 6.

Nitric oxide synthase is important for the effects of iAβo on the frequency of miniature synaptic currents in the neuronal ensemble. (a) Micrograph showing the area of the primary hippocampal culture in which mPSC were measured from the recorded neuron (RN), as well as the NO fluorescence for RN and of the neighboring neurons to RN (NN). (b, c) Representative recordings (b) and quantification of mPSC frequency (c) obtained during the course of 20 min in the absence (control) and the presence of 200 nM iAβo, together with the pre‐incubation with L‐NAME (200 µM for 20–30 min). mPSC were recorded in the presence of 500 nM TTX (V _h = −60 mV). (d) Quantification of mPSC frequency at 20 min (obtained from data marked inside gray rectangle from plot in (c). (e–h) Relative levels of NO (expressed as normalized fluorescence) obtained throughout the course of the experiment and at 20’ for RN (e and f, respectively) and NN (g and h, respectively). See details in Section 2.6. Line and bar graphs represent the average ± SEM. Control (n = 9), L‐NAME (n = 8), iAβo (n = 11) and iAβo + L‐NAME (n = 10) for RN and control (n = 97), L‐NAME (n = 102), iAβo (n = 119) and iAβo + L‐NAME (n = 102) for NN. One‐Way Welch's ANOVA with Games–Howell post hoc test for (d): F(3, 34) = 60.309, p = 1.07E‐13. p‐values for post hoc test: Control vs. iAβo: 1.06E‐08, L‐NAME vs. iAβo + L‐NAME: 7.80E‐3, iAβo vs. iAβo + L‐NAME: 1.40E‐08. One‐Way Welch's ANOVA with Games–Howell post hoc test for (f): F(3, 34) = 21.926, p = 4.41E‐8. p‐values for post hoc test: Control vs. iAβo: 2.53E‐05, L‐NAME vs. iAβo + L‐NAME: 3.03E‐3, iAβo vs. iAβo + L‐NAME: 1.18E‐03. One‐Way Welch's ANOVA with Games–Howell post hoc test for (h): F(3, 416) = 40.763, p = 4.11E‐23. p‐values for post hoc test: Control vs. iAβo: 6.44E‐20, L‐NAME vs. iAβo + L‐NAME: 2.16E‐3, iAβo vs. iAβo + L‐NAME: 8.85E‐09. ** denotes p < 0.01, *** p < 0.001. See Figure S6 for experiments obtained in the presence of SNAP and CPTIO and Figure S7 for experiments using iNOS inhibitor (1400W)