Figure 5.

Fluorescence intensity in the olfactory bulbs (panels (A,D)) and left and right trigeminal nerves (panels (B,C,E,F)) after intranasal administration of Cy7-labeled Exendin-4 and insulin with or without L-penetratin calculated from the imaging data presented in Figure 4. We corrected the L-penetratin-induced Cy7 fluorescence loss using the relative fluorescence shown in Figure 3E,F (70% for Cy7-Exendin-4 and 48% for Cy7-insulin). Panels G and H show the fluorescence ratios of olfactory bulbs per trigeminal nerves at 15, 30, and 60 or 120 min after intranasal administration of Cy7-Exendin-4 (G) and Cy7-insulin (H) with or without L-penetratin. Data are expressed as the mean ± SEM of n = 3–5. * (p < 0.05) and ** (p < 0.01) indicate a significant difference from the control intranasal administration group without L-penetratin.