TAC1 and Nasal congestion: Stimulation of transient response potential (TRP) calcium ion channels in the nose by nonspecific environmental factors such as temperature, mechanical, osmotic or chemicals and irritants is known to activate nasal afferent nerve fibers that lead to their depolarization and release of neuropeptides (substance P, neurokinin A, calcitonin gene related peptide), as well as signaling through the central nervous leading to subsequent efferent responses (i.e., glandular, and/or vascular responses manifested as rhinorrhea and nasal congestion, respectively) [11,12].