Pulmonary Distribution of VIP Gene Products

VIP is synthesized in nerve cell bodies and transported by axoplasmic flow to nerve terminals ganglia containing VIP reactive cell bodies are found in great profusion in the walls of the trachea and major bronchi (Uddman et al., 1978 Dey et al., 1981). Nerves with VIP immunoreactivity have been found in the airways of most mammalian species studied (Springall etal., 1988 Barnes etal., 1991). This immunoreactivity is localized both to nerves and to nglia in the airway wall VIP-containing neurons in the airway predominantly innervate bronchial 

VIP-immunoreactive fibers are found within the smooth muscle and in association with vessels and mucous glands (Dey et al., 1981 Ghatei et al., 1982 Laitinen et al., 1985 Springall et al., 1988). In some mammalian species, VIP has been localized to nerves running beneath the epithelium, though these subepithelial fibers appear to be of sensory origin (Barnes etal., 1991). The presence of VIP in the airways has been confirmed by measurements of the VIP content of extracts of airway tissue (Ghatei et al., 1982, 1983). 

Changes in the distribution of VIP-immunoreactive nerves have also been reported in airways (or airway biopsy specimens) from patients with airway disease. Ollerenshaw et al. (1989) reported finding few, if any, VIP-containing nerves in the airways of asthmatic patients in contrast, such nerves were found in the airways of non-asthmatic subjects who served as controls. These data have not been widely reproduced another group who studied the VIP content of bronchoscopically obtained airway samples from mildly asthmatic and nonasthmatic subjects was unable to detect a difference 

Airway VIP content has also been measured in patients with the respiratory distress syndrome of the newborn. The VIP content of airways of children who died of acute respiratory distress syndrome did not differ from that of airways of age-matched control children who died of non-respiratory causes (Ghatei et al., 1983). 

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