VASOACTIVE-INTESTINAL-PEPTIDE (VIP) AND RELATED PEPTIDES AS ANTIASTHMA AND ANTIINFLAMMATORY AGENTS

VIP relaxes airway smooth muscle and reduces or prevents bronchoconstriction produced in animals by a variety of bronchoconstrictor agents. The peptide is present in nerve fibers and nerve endings supplying key structures in the lung, and binds to specific receptors that are widely distributed in that organ. VIP may also serve as a normal transmitter of nonadrenergic relaxation of the airways, and may be lacking in asthmatic airways. In asthmatic patients, however, VIP given by aerosol was of limited success in relieving bronchoconstriction, probably because of its rapid degradation by airway peptidases. Helodermin, a closely related peptide, also relaxes tracheobronchial smooth muscle and its action is more prolonged than that of VIP. For this reason, helodermin may prove more useful in asthma. Recently, both VIP and helodermin have been found also to protect the lung against acute inflammatory injury in various experimental models. Both peptides may, therefore, be beneficial in the prevention and management of the acute lung injury of the Adult Respiratory Distress Syndrome (ARDS).