Fig. 1.
A: site of retrograde tracer injection (red spot) of an original brain of the rat medulla (bregma −13.32 mm) according to Paxinos and Watson's rat brain atlas (30). The bright red area indicated by the arrow demonstrates the injection site of rhodamine-labeled fluorescent microspheres in the nucleus ambiguus. Scale bar in A represents 1 mm. B–E: confocal microscopic images demonstrate triple-fluorescent labeling in the nucleus tractus solitarius (NTS) (bregma −13.56 mm) of a rat. Arrows indicate neurons stained with vesicular glutamate transporter 3 (VGLUT3), GABAA receptors, retrograde tracer originating from nucleus ambiguus, and colabeling of VGLUT3, GABAA, and tracer, respectively. Scale bars represent 20 μm.