VIP and chronic obstructive pulmonary disease: As in allergic bronchial asthma or rhinitis, pro- and anti-inflammatory mediators of inflammation such as tachykinins [32], vasoactive intestinal polypeptide (VIP) [33], histamine [34], nitric oxide [35,36], leukotrienes [37], or opioids [38] and other cytokines [11] are likely to play a role in the regulation of basic pathophysiological mechanisms occurring in COPD.