Just for mice

Stereotaxic injections were performed as previously described(Krashes et al., 2011 (link)). Mice were anaesthetised with isoflurane and placed into a stereotaxic apparatus (Stoelting Just for Mice). For postoperative care, mice were injected intraperitoneally with meloxicam (0.5 mg per kg). After exposing the skull via small incision, a small hole was drilled for injection. A pulled-glass pipette with 20–40 mm tip diameter was inserted into the brain and virus was injected by an air pressure system. A micromanipulator (Grass Technologies, Model S48 Stimulator) was used to control injection speed at 25 nl min⁻¹ and the pipette was withdrawn 5 min after injection.
Behavioural testing testing (food intake screening, pellet and water intake studies) All animals were singly housed for at least 2.5 weeks following surgery and handled for 10 consecutive days before the assays to reduce stress response. Studies were conducted in a home-cage environment near the beginning of the light cycle (9 am) for food intake screening, pellet and water intake studies and in specialized environments for hole-board, Y-maze, open-field, elevated zero maze, TMT and social interaction assays. All Agrp-ires-Cre animals (fed^GFP, fasted^GFP and fed^ChR2 groups) were photostimulated for 10 minutes in the homecage in the absence of food before being placed in the behavioral apparati.