Identification of the microinjection sites in the nucleus tractus solitarii (NTS). (a) A representative photomicrograph showing the NTS microinjection site and the location of this microinjection site based on the rat brain atlas. The arrow indicates the injection site. (b) Functional identification of the NTS with microinjections of glutamate (Glu; 300 pmol in 50 nL) in one rat. Unilateral glutamate produced decreases in arterial pressure (AP) and HR.