Fig 8. Proposed NE signaling cascade in T-lymphocytes.

T-lymphocytes have been shown to express all adrenergic receptors, and NE has binding affinity to each isoform. In both CD4+ and CD8+ cells, NE appears to reduce proliferation via β-receptor canonical signaling (solid arrows) independent of redox events. CD4+ cells utilize the α2 receptor while CD8+ cells use all four adrenergic receptors to initiate redox signaling (dashed arrows) to affect specific subsets of cytokines. In both cells, the addition of MitoTempol can decrease this increase in mitochondrial O₂^●- and reverse the changes in specific cytokine expression.