FIGURE 1.

Injection of NMDA into vLPO or into MPA inhibits the BAT thermogenesis evoked by cold exposure. A, Nanoinjections of N-methyl-D-aspartate (NMDA, 0.2 mmol/L, 60 nL) in the region of the horizontal limb of the diagonal band of Broca (HDB, solid line) had no effect on brown adipose tissue sympathetic nerve activity (BAT SNA), BAT temperature (T_BAT), expired CO₂ (Exp CO₂), core body temperature (T_CORE), mean arterial pressure (MAP) or heart rate (HR). In contrast, nanoinjections of NMDA into the ventral part of the lateral preoptic area (vLPO, dashed line) or into the medial preoptic area (MPA; dotted line) significantly inhibited BAT SNA and reduced T_BAT, Exp CO₂, and HR. B–D, Composite maps of the NMDA nanoinjection sites plotted on schematic drawings through the preoptic area (POA) at +0.1 mm (B), −0.2 mm (C), and −0.6 mm (D) from bregma, accompanied by corresponding histological sections containing the fluorescent beads marking representative NMDA nanoinjection sites (white arrows). X: indicates injections targeting the region of the HDB, ▲: indicates injections targeting the vLPO, and O: indicates injections targeting the MPA. 3 V, third ventricle; ac, anterior commissure; LPO, lateral preoptic; MnPO, median preoptic area; oc, optic chiasm;