Figure 3.

Central injection of CGRP through a cannula elicits light aversion. A, Time spent in the light zone by C57BL/6J mice at 2.7 × 10⁴ lux (left). The mice were preexposed to the chamber twice (Pre1, Pre2), then treated with vehicle (Veh, n = 11) or CGRP (2 μg/mouse, ICV, n = 13) on treatment day (Tx), followed by a Post measurement. After intracerebroventricular injection, CGRP-treated mice spent less time in light compared with vehicle (*p < 0.05, ***p < 0.001) and compared with Pre2 and Post as indicated by brackets (****p < 0.0001). Right panel shows the mean time (±SEM) in light per 5 min interval for individual mice on treatment day, **p < 0.01. Data are from two independent experiments. B, Resting time in light and dark zones measured at the same time as light aversion with mice shown in A. CGRP-treated mice spent significantly more time resting in the dark compared with vehicle-treated mice and Pre2 and Post periods (mean ± SEM, **p < 0.01, ***p < 0.001, ****p < 0.0001).