Effects of smoke exposure on neuropeptide Y‐containing nerves in airway of early postnatal mice

Abstract

Abundant epidemiological data show that maternal smoking during pregnancy or neonatal and infant periods increases the incidence of respiratory illnesses later in life. However, the underlying mechanism remains unclear. Neuropeptide Y (NPY) produces vasoconstriction of airway vasculature and our previous PCR array data shows that the NPY gene is enhanced by smoke exposure during early prenatal periods. The goal of this proposal is to study the effects of early postnatal smoke exposure on NPY airway innervation. New born mice were directly exposed to either smoke or filtered air for 1, 5 and 10 days (6 hours per day) and the density of NPY‐containing nerves in airway smooth muscle was measured by immunocytochemistry 16 hours after the last smoke exposure. NPY‐containing fibers were mainly found around blood vessels and airway smooth muscle. NPY nerve fiber density in airway smooth muscle were significantly increased from 0.88 0.14 to 4.81 0.68 after 5 days smoke exposure and from 0.69 0.11 to 3.46 0.42 after 10 days smoke exposure. 1 day smoke exposure increased NPY from 0.55 0.07 to 1.18 0.29, but difference was not significant. These data suggest that cigarette smoke exposure enhances NPY expression in airways of newborns.Funded By: NIH HL 35812 and NIH ES014618