Signaling pathways of the acute hypoxic ventilatory response in the nucleus tractus solitarius

The nucleus tractus solitarii (nTS) provides the initial central synaptic r elay to peripheral chemoreceptor afferent inputs elicited by changes in oxy gen tension. Insofar, the overall cumulative evidence pointing towards the N-methyl-D-aspartate (NMDA) glutamate receptor as the critical receptor und erlying the early component of the hypoxic ventilatory response (HVR) is re viewed in detail. In addition, we will present recent findings supporting a role for platelet-derived growth factor (PDGF) beta receptor activation in modulation of the late phase of HVR. This evidence underscores the proposa l of a working model for intracellular signaling pathways, downstream to th e NMDA glutamate and PDGF-beta receptors in nTS neurons, which may contribu te to both the ventilatory characteristics of the acute hypoxic response an d to subsequently occurring functional adaptations and synaptic plasticity phenomena. (C) 2000 Elsevier Science B.V. All rights reserved.