Modulation of the sympathetic response to acute hypoxia by the caudal ventrolateral medulla in rats.

J Physiol. 2009 Jan 15;587(Pt 2):461-75. Mandel DA, Schreihofer AM. “Hypoxia elevates splanchnic sympathetic nerve activity (SNA) with differential effects during inspiration and expiration by unresolved central mechanisms”. The authors tested the hypothesis whether baro-activated CVLM neurons contribute to sympathetic responses to acute hypoxia. Additionally the authors also tested whether selective inhibition of excitatory or inhibitory actions on the CVLM would alter the sympathetic responses to hypoxia. In this study, the authors demonstrated that stimulation of peripheral chemoreceptors by hypoxia produced differential responses in baro-activated CVLM neurons. Blocking excitation and inhibition of the CVLM augmented or reduced the sympathetic response to acute hypoxia respectively. This suggests that both glutamate and GABA in the CVLM could be involved in mediated sympathetic responses to acute hypoxia.-Madhan