Ombeline Hoa, Chrystel Lafont, Pierre Fontanaud, Anne Guillou, Yasmine Kemkem, Rhonda D Kineman, Raul M Luque, Tatiana Fiordelisio Coll, Paul Le Tissier, Patrice Mollard

Extensive efforts have been made to explore how the activities of multiple brain cells combine to alter physiology through imaging and cell-specific manipulation in different animal models. However, the temporal regulation of peripheral organs by the neuroendocrine factors released by the brain is poorly understood. We have established a suite of adaptable methodologies to interrogate in vivo the relationship of hypothalamic regulation with the secretory output of the pituitary gland, which has complex functional networks of multiple cell types intermingled with the vasculature. These allow imaging and optogenetic manipulation of cell activities in the pituitary gland in awake mouse models, in which both neuronal regulatory activity and hormonal output are preserved. This methodology is now readily applicable for longitudinal studies of short-lived events (e.g. calcium signals controlling hormone exocytosis) and slowly-evolving processes such as tissue remodelling in health and disease over a period of days to weeks.