Monosynaptic connection from caudal to rostral ventrolateral medulla in the baroreceptor reflex pathway

S.K. Agarwal and F.R Calaresu

Department of Physiology, University of Western Ontario, London, Ont (Canada)

We already know that CVLM projects to RVLM; this article is one reason why that conclusion has been made. So the authors hypothesized that the CVLM neurons are activated by activation arterial baroreceptors, activation of NTS and there is a monosynaptic between the CVLM and RVLM.  In urethane anesthetized rats they recorded from several neurons within that CVLM. The tested the activity of these neurons by giving a bolus of PE to increase blood pressure and in order to activate the CVLM neurons. By using electrophysiology, they were able to record the activity of the neurons directly. They found that 20 were actually activated. Only 6 were activated by stimulation of the NTS. The same 6 neurons were activated by antidromatic stimulation of the RVLM.   The conclusion that they came to from the experiment were the following 1.) NTS has excitatory inputs to CVLM  2.) CVLM has neurons that are barosensitive and send inhibitory inputs to RVLM 3.) There is a monosynaptic connection between the CVLM and RVLM.