Figure 4.

Anti-PACAP antibodies potentiate light-induced phase advances of the wheel-running activity rhythm in vivo. Hamsters were maintained under constant conditions in darkness to express free-running circadian rhythms. (A– C) Sequential daily activity records from three hamsters representing the effects of various treatments. Each horizontal bar represents 24 h. (D) The phase advance in the anti-PACAP antibody plus light group was significantly different from that for either light exposure or anti-PACAP antibodies alone. Light exposure (20 lux, 15 min) at CT 18 (6 h after activity onset) after vehicle (2 μl) was administered by ICV injection induced a 0.74 ± 0.29-h phase advance. Anti-PACAP antibodies administered before light exposure significantly potentiated the light-induced phase advance (1.58 ± 0.33 h, P < 0.05). Anti-PACAP antibodies themselves did not induce significant phase shifts (+0.06 ± 0.12 h). n/condition is shown above the bars.