Fig. 5.

Optostimulation of tanycytes triggers an acute hyperphagia. (A) Optostimulation of tanycytes had an effect on food intake during the 40-min test. Animals were in an open field with two cups (changed alternately) that contained a slightly enriched pellet. Stimulation occurred for 20 min at the same frequency as the in vitro study and for 20 min left free-running. Video tracking was used to analyze animal behavior. (B) Time course of the behavior response after activation of tanycytes by CatCh versus controls. Adenovirus vector expression seems to be cleared by cells after 21 d postinfection. The optimal period for the expression is around 16 d (two-way repeated-measures ANOVA, *P = 0.004, followed by Sidak’s post hoc analysis; n = 8 and 7 mice per group; for all box plots, the box represents the upper and lower quartiles, the central line the median, and the whiskers the maximum and minimum values; the open square indicates the mean). (C) The optostimulation of tanycytes induces an acute hyperphagia in animals when received between ZT 7 and 10 (Mann–Whitney U test, *P = 0.02; n = 7 mice in each group, the box represents the upper and lower quartiles, the central line the median, and the whiskers the maximum and minimum values). (D) Nineteen hours of fasting prior to the test abolished the effect of tanycyte activation on food intake (ZT 7 to 10; Mann–Whitney U test, P > 0.05; n = 4 mice per group, the box represents the upper and lower quartiles, the central line the median, and the whiskers the maximum and minimum values). No effect was observed if animals were acutely fasted 1 h prior to the test (SI Appendix, Fig. S5A). NS, not significant. (E) The ratio of the time spent immobile in the food zone to the time spent immobile in the nonfood zone during the test. Activation of tanycytes will trigger an acute hyperphagia (time spent immobile “eating”) after approximatively 25 min (Friedman test, *P = 0.02; n = 7, mean ± SEM).