Fig. 8.
Working model of signaling pathways to hypoxia-induced phrenic motor plasticity. Unique pathways are elicited by 5-HT2A receptors (i.e. the Q pathway; Dale-Nagle et al., 2010), VEGF receptors, and A2A receptors (i.e. the S pathway). These downstream signaling molecules have the potential to play critical roles in enhanced pMF following repetitive AIH. Results from this study indicate that all of these respective molecules are upregulated by 3×wAIH, consistent with the greater capacity for functional plasticity.