Figure 4

PACAP enhanced AMPA- and NMDA-evoked Ca²⁺ responses in a subset of mouse SCN neurons. Optical imaging techniques were used to estimate Ca²⁺ responses to AMPA and NMDA in ventral SCN neurons during the night (ZT 15–17). (A) AMPA (25 μM)-induced Ca²⁺ transients were also enhanced by the pre-treatment with PACAP (10 nM, 240 sec). (B) NMDA (25 μM)-induced Ca²⁺ transients were also enhanced by the pre-treatment with PACAP (10 nM, 240 sec). (C) Histograms summarizing PACAP modulation of AMPA and NMDA-evoked Ca²⁺ transients in the SCN. The enhancement of AMPA-evoked Ca²⁺ transients was mimicked by the PAC1 receptor agonist maxadilan (Max, 100 nM, 240 sec). This data was collected in the presence of TTX. Asterisks indicate values that are significantly greater than those of the AMPA- or NMDA-treated groups (P < 0.05)