Role of rostral ventrolateral medulla centrally mediated pressor responses

Full cite: Kiely JM, Gordon FJ. Role of rostral ventrolateral medulla centrally mediated pressor responses. Am J Physiol Heart Circ Physiol 267:H1549–H1556, 1994. Role of rostral ventrolateral medulla centrally mediated pressor responses James M. Kiely and Frank J. Gordon Department of Pharmacology, Emory University of Medicine, Atlanta, Georgia 30322 This paper is one of the first to look at how the RVLM mediates different central pressor responses, in particular how EAA receptors play a role in the proliferation of these responses. In this particular experiment they used female Sprague-Dawley rats, recorded BP, and instrumented for sciatic nerve stimulation (SPR). Electrodes were positioned into the periventricular nucleus (*which I thought was pretty cool*). Then a head surgery was performed to expose the brainstem, similar to how we prepare for our microinjection experiments. Kyn was injected bilaterally and there was no BP response, similar to in our experiments. When Kyn was injected in the RVLM, the hypothalamus’s pressor responses were intact. Injection of kainic acid increased BP for a short period of time (= 10s), after that point BP fell around 35 mmHg (~5 min). SPR and PFH responses were attenuated, PVN and AH responses were intact. PFH and PVN responses were reduced following injection of muscimol; lidocaine into RVLM abolished SPR, and greatly reduced the PFH and PVN responses. This paper is likely one of the first to demonstrate that the PVN and PFH have spinal projections of their own and are able to function at least somewhat independently from RVLM. Also it seems that SPR are almost exclusively mediated through the RVLM. It would be interesting to see how the activity of PVN and PFH might be altered during an RVLM knockout or blockade. I also do not know whether or not PVN or PFH are barosensitive. I think that at some point we are either going to have to integrate PVN into our experiments or knock it out in some way, because it may very well be playing a role in our responses. MTL