FIGURE 5.

Activation of vLPO neurons inhibits BAT thermogenesis evoked by nanoinjection of NMDA, but not bicuculline, in rRPa. A, Nanoinjections of NMDA (0.2 mmol/L, 60 nL) in the vLPO revert the elevated levels of BAT SNA, BAT temperature (T_BAT), expired CO₂ (Exp CO₂), core temperature (T_CORE), mean arterial pressure (MAP), and heart rate (HR) evoked by bicuculline (1 mmol/L, 60 nL) nanoinjection in the rRPa. B, Nanoinjections of NMDA (0.2 mmol/L, 60 nL) in the vLPO on the elevated levels of BAT SNA, T_BAT, Exp CO₂, T_CORE, MAP, and HR evoked by nanoinjection of NMDA (0.2 mmol/L, 60 nL) in the rRPa. C, composite mapping of the NMDA nanoinjection sites plotted on drawing of rRPa at −12 mm caudal to bregma; composite mapping of the NMDA nanoinjection sites plotted on drawing of vLPO at −0.6 mm caudal to bregma; and histological section containing the fluorescent beads marking a representative nanoinjection. D, Composite mapping of the bicuculline nanoinjection sites plotted on drawing of rRPa at −12 mm caudal to bregma; and composite mapping of the NMDA nanoinjection sites plotted on drawing of vLPO at −0.6 mm caudal to bregma; and histological section containing the fluorescent beads marking a representative nanoinjection. LPO, lateral preoptic; MPA, medial preoptic area; oc, optic chiasm; py, pyramidal tract; rRPa, rostral raphe pallidus; 3 V, third ventricle; vLPO, ventral part of the lateral preoptic area.