HOW IN UTERO AND NEONATAL NICOTINE EXPOSURE (DNE) ALTERS GABAAR-Α1 EXPRESSION ON HYPOGLOSSAL MOTOR NEURONS (XIIMNS)

Abstract

Developmental nicotine exposure (DNE) alters the function of hypoglossal motor neurons (XIIMNs), which are involved in breathing, suckling, swallowing, and chewing. Alterations occur by activation of nicotinic acetylcholine receptors (nAChRs) on GABAergic neurons. Nicotine was delivered to pregnant rats through drinking water two weeks prior to birth to expose the developing fetuses, with exposure continuing after birth via breast milk. Comparisons between nicotine-exposed and unexposed rats by immunohistochemical analysis was completed between two age groups, postnatal (P)1-P5 and P10-P12. A comparison between exposed and unexposed rats in each age group yielded a trend of DNE neonates towards greater GABAAR-α1 expression in the hypoglossal motor nucleus. These results provide insight into the unknown mechanism behind abnormalities of the tongue motor system that have been observed in nicotine exposed infants, including weak suckling, poorly coordinated swallowing, and breathing abnormalities such as Sudden Infant Death Syndrome.