1. Excitatory amino acid (EAA)-mediated neural transmission in the rostral ventrolateral medulla (RVLM) is important for many cardiovascular reflexes, although the receptor subtypes involved vary depending on the specific response. 2. Although injection of the EAA ionotropic receptor antagonist kynurenic acid into the RVLM has no effect on baseline arterial pressure, this lack of effect appears to result from EAA inputs to RVLM exciting both excitatory and inhibitory mechanisms within the RVLM. 3. The balance between EAA-mediated excitation and inhibition of RVLM neurons may be shifted to excitation in experimental models of hypertension. 4. The excitatory influence that EAA inputs to the RVLM have on vasomotor neurons in the RVLM may involve a sarthran-sensitive intermediary in the RVLM.