Fig. 6.

Glutamate transmission in the RVLM mediates cardiovascular responses to microinjection of α,β-methylene ATP into the NTS. a Averaged curve of responses in hindlimb vascular conductance (HVC) induced by microinjection of α,β-methylene ATP (α,β-me ATP; 2 mM) in the nucleus tractus solitarii (NTS) before and after blockade of glutamate receptors in the rostral ventrolateral medulla (RVLM) with kynurenate (50 mM). Black squares, averaged curve during control; in dark graycircles, averaged curve after blockade; in light gray, standard error of the mean. b Pooled changes in arterial blood pressure and heart rate evoked by α,β-me ATP into the NTS before (white) and after (black) microinjections of kynurenate into the RVLM. c Photomicrograph of a coronal bulbar section representative of the group, showing verification of the injection site into the RVLM. nA nucleus ambiguus; Py pyramidal tract; V trigeminal nucleus; sp V spinal trigeminal tract; RVLM rostral ventrolateral medulla