Non-NMDA receptors in the rostral ventrolateral medulla mediate somatosympathetic pressor responses.

James M. Kiely and Frank J. Gordon

Journal of the Autonomic Nervous System, 43(1993) 231-240

      This paper studied the role of excitatory amino acid receptors in the rostral ventrolateral medulla (RVLM) in mediating somatosympathetic pressor response (SPR). This SPR is prompted by sciatic nerve stimulation, something that I do within my experiments.  Female Sprague-Dawley rats were anesthetized with urethane and then followed by microinjection protocol of NMDA (D-AP7) or non-NMDA (DNQX) antagonists. By differentially blocking both NMDA and non-NMDA receptors throughout several protocols, they found that the non-NMDA receptors were the receptors actually mediating the SPR. This paper offers one of the earliest pieces of evidence of interneurons in RVLM, due to the fact that D-AP7 prevented the blockade and reversal of SPR by DNQX. The observations of this paper suggest the possibility of sympathoinhibitory interneurons within the RVLM which can be stimulated by activation of NDMA receptors. A few issues I have with this paper is the fact that they were able to illicit such high pressor responses from sciatic nerve stimulation (about 45 mmHg) while I can only increase pressure by about (15 mmHg) with a similar stimulation.

Posted by Max