TAC1 and asthma: The activation of NK1-R by substance P is known to potently stimulate epithelial goblet cell secretion, whereas the neurokinin A/NK2-R signaling, remarkably upregulated in the lung of asthmatic subjects and mice [70,71], appears to influence a variety of pathological symptoms and processes in asthma, such as inflammation and AHR [51,72,73].