TACR2 and chronic obstructive pulmonary disease: Tachykinins have been proposed to play an important role in human respiratory diseases such as bronchial asthma and chronic obstructive pulmonary diseases (COPD), as they have been shown to activate the neurokinin (NK)-1 and NK-2 receptors, leading to potent effects on airway smooth muscle tone and secretions, bronchial circulation, and inflammatory and immune cells [10].