The rostral raphe pallidus (rRPa) contains sympathetic premotor neurons controlling thermogenesis in brown adipose tissue (BAT). We sought to determine if a tonic activation of glycine_A receptors (Gly_AR) in the rRPa contributes to the inhibitory regulation of BAT SNA and of cardiovascular parameters in anesthetized rats. Nanoinjection of the Gly_AR antagonist, strychnine (STR), into the rRPa of intact rats increased BAT sympathetic nerve activity (SNA, peak: +495%), BAT temperature (TBAT, +1.1 ºC), expired CO₂, (+0.4 %), core body temperature (TCORE, +0.2 ºC), arterial pressure (MAP, +4 mmHg) and heart rate (HR, +57 bpm). STR into rRPa in rats with a post-dorsomedial hypothalamus transection produced similar increases in BAT thermogenic and cardiovascular parameters. Glycine (GLY) nanoinjection into the rRPa evoked a potent inhibition of the cooling-evoked increases in BAT SNA (nadir: -74 %), TBAT (-0.2 ºC), TCORE (-0.2 ºC), expired CO₂ (-0.2 %), MAP (-8 mmHg), and HR (-22 bpm), but had no effect on the increases in these variables evoked by STR nanoinjection into rRPa. Nanoinjection of GABA into the rRPa inhibited the STR evoked BAT SNA (nadir: -86 %), and reduced the expired CO₂ (-0.4 %). Blockade of glutamate receptors in rRPa reduced the STR-evoked increases in BAT SNA (nadir: -61 %), TBAT (-0.5 ºC), expired CO₂ (-0.3 %), MAP (-9 mmHg) and HR (-33 bpm). We conclude that a tonically active glycinergic input to the rRPa contributes to the inhibitory regulation of the discharge of BAT sympathetic premotor neurons and of BAT thermogenesis and energy expenditure.