Abstract:
Nicotine has been shown to increase the risk of anxiety related disorders in adulthood
(Slawecki, Gilder, Roth, & Ehlers, 2003). Early nicotine exposure may negatively affect
the development of the adolescent brain(Morissette, Tull, Gulliver, Kamholz, &
Zimering, 2007). The bed nucleus of the stria terminalis has been shown to have major
projections to the PVNmp that regulates the brain and body’s reaction to stress as well as
influences activity of the HPA axis. This study investigated morphological changes of
dendrites on neurons located in the bed nucleus of the stria terminalis following
adolescent nicotine exposure. Male Sprague-Dawley rats were administered nicotine
(0.5mg/kg/day) 3 days a week for 2 consecutive weeks, starting at postnatal day P (32).
17 days following the end of dosing, at postnatal day P (60), brains were processed for
Golgi-Cox staining and neurons were digitally reconstructed for branch order and
Sholl(Sholl, 1953) analysis. Nicotine pretreatment produced an increase in the number of bifurcations and total length of dendrites. Nicotine pretreatment also increased the
average length of dendrites, suggesting that growth of existing branches is occurring as
well as formation of new branches. Sholl analysis also revealed an increase in the
number of intersections with concentric spheres, increased amount of dendritic material
within concentric spheres, and an increase of dendritic branching within concentric
spheres occurring between 20-300μm from the soma in dendrites.
