Neuropeptide Y in rostral raphe pallidus activates brown adipose thermogenesis

The rostral raphe pallidus (rRPa) in the rostral ventromedial medulla contains sympathetic premotor neurons controlling brown adipose tissue (BAT) thermogenesis. To determine if a neuropeptide Y (NPY) input to rRPa neurons could influence BAT thermogenesis and energy expenditure, nanoinjections of NPY (20pmol/100nl) were made into the rRPa of urethane/chloralose‐anesthetized, artificially‐ventilated Wistar rats. NPY injection into rRPa elicited a large and prolonged increase in BAT sympathetic nerve activity (SNA), BAT temperature, core body temperature, heart rate and respiration. Prior injection of the NPY Y2 receptor antagonist, BIIE346 (5pmol/60nl) prevented the autonomic responses evoked by subsequent injection of NPY into the rRPa. We conclude that NPY‐inputs to neurons in rRPa represent a potential source of sympathoexcitatory drive to BAT and cardiac sympathetic premotor neurons. Supported by grants from NINDS: NS040987(SFM), NS066159(MH), F30 NS070374(DC).