Pharmacological Modulation of Neural Responses

Animals were randomly allocated into three different groups: the leptin group received a single injection of leptin, 500 ng/50 µl (Peprotech); the fractalkine group received a single injection of fractalkine, 100 ng/50 µl (Peprotech); the control group received the vehicle (0.9% NaCl/50 µl). The choice of leptin and fractalkine dose was based on previous studies and adapted to our route of administration, the subcutaneous tissue (Souza et al., 2013 (link); Tian et al., 2011 (link); Duan et al., 2007 (link)). leptin, fractalkine or saline were injected using an insulin syringe (BD Ultra-Fine^®, 29G) subcutaneously (SC) between the five callosities of the paw, the same region to which experimental mechanical and thermal stimuli were applied.