Figure 2.

Organ-specific metabolic effects of neuroendocrine stress response induced by inhaled irritants. Irritant pollutants interacting with the lung (solid green arrow) result in sensory signals and pulmonary mediators that cause neuroendocrine activation in the brain (solid red arrow). Activation of the hypothalamic-pituitary-adrenal (HPA; solid black arrows) and sympathetic-adrenal-medullary (SAM; dotted blue arrow) axes lead to the release of stress hormones from the adrenal gland into the circulation (solid purple arrow). These stress hormones can mediate organ-specific effects through activation of adrenergic and glucocorticoid receptors (solid gold arrows). In addition, nerves originating from the spinal ganglion innervate the visceral organs and mediate direct sympathetic activation (dotted black arrows). ↑, increase in response; ↓, decrease in response; Δ, change in response depending on irritant pollutant; Hyp, hypothalamus; CRH, corticotropin releasing hormone; ACTH, adrenocorticotropic hormone.