A bidirectional network for appetite control in zebrafish. Caroline Lei Wee
Erin Yue Song, Robert Evan Johnson, Deepak Ailani, Owen Randlett, Ji-Yoon Kim, Maxim Nikitchenko, Armin Bahl, Chao-Tsung Yang, Misha B Ahrens, Koichi Kawakami, Florian Engert, and Sam Kunes.
eLife 8:e43775 (2019). DOI:10.7554/eLife.43775
Medial and lateral hypothalamic loci are known to suppress and enhance appetite, respectively, but the dynamics and functional significance of their interaction have yet to be explored. Here we report that, in larval zebrafish, primarily serotonergic neurons of the ventromedial caudal hypothalamus (cH) become increasingly active during food deprivation, whereas activity in the lateral hypothalamus (LH) is reduced. Exposure to food sensory and consummatory cues reverses the activity patterns of these two nuclei, consistent with their representation of opposing internal hunger states. Baseline activity is restored as food-deprived animals return to satiety via voracious feeding. The antagonistic relationship and functional importance of cH and LH activity patterns were confirmed by targeted stimulation and ablation of cH neurons. Collectively, the data allow us to propose a model in which these hypothalamic nuclei regulate different phases of hunger and satiety and coordinate energy balance via antagonistic control of distinct behavioral outputs.
Figure: Calcium imaging of cH and LH by using transgenic zebrafish. By addition of paramecia (food), cH activity was reduced and LH activity was increased.
▶This study is based on the previous study.