Figure 4.

Ex vivo fluorescence imaging of brain slices and trigeminal nerve bundles after intranasal administration of Cy7-labeled Exendin-4 (panel (A)) and insulin (panel (B)) with or without L-penetratin to Sprague-Dawley rats. The tissues were isolated at 15, 30, and 60 or 120 min after administration, and fluorescence was measured with the same settings for all treatment groups. The images show a typical result obtained in one experiment. Separate experiments under the same conditions yielded similar results (n = 3–5).