Fig. 1. Micrographs showing planar and cross sections of the ganglion nodosum and the medulla, immunostained with glutamate or NMDAR1 antisera. (A) Glutamate-like immunoreactivity (IR) in vagal nerve fibres proximal to the ganglion nodosum. (B) Glutamate-like IR in numerous cell bodies (arrow) within the ganglion nodosum. (C) Glutamate-like IR in almost all vagal nerve fibres (arrow) in the medulla projecting toward the vagal sensory area (Xs). (D,E) NMDAR1-like IR in fibres (arrow, D) and cell bodies (arrow, E) in the intermediate Xs (see F). (F) Dorsal view of the sculpin hindbrain. VII, facial nerve; IX, glossopharyngeal nerve; X, vagus nerve (two major branches); ovals indicate the positions of the Xs columns on each side of the medulla (a, rostral; b, intermediate; c, caudal portion of the Xs). Arrowhead points towards the caudal end of the fourth ventricle (4V), the obex. (G) Nissl stained cross section through the intermediate Xs (indicated in F) showing the precise location of the Xs and the vagal motor area (Xm) in the medulla. Scale bars, 1 mm (F), 100 µm (A,C,G), 50 µm (B,D) and 10 µm (E).