[Abstract Title]. - Society for Neuroscience

Program#/Poster#: 279.1/MM15
Topic: E.01.e. Sexual differences
Support: NIH Grant KO2 MH01497
NIH Grant RO1 MH47538
Title: Steroid-sensitive vasopressin innervation in male and female mice
Authors: *B. D. ROOD, G. J. DE VRIES;
Neurosci. & Behavior, Univ. Massachusetts, Amherst, MA
Abstract: Vasopressin-immunoreactive fibers derive from a few distinct nuclei in the mouse
brain. Large magnocellular neurons in the paraventricular nucleus of the hypothalamus and
supraoptic nucleus project to the posterior pituitary, where they release vasopressin into the
bloodstream. Smaller neurons in the paraventricular nucleus, but also in the suprachiasmatic
nucleus, bed nucleus of the stria terminalis (BNST), and medial amygdala, project throughout the
brain, where they release vasopressin as a neurotransmitter or neuromodulator. The distribution
of fibers emanating from these nuclei is thought to be overlap minimally suggesting that
vasopressin may have several mutually exclusive functions in the brain. The first step in
understanding the relationship between structure and function in the vasopressin system is to
elucidate the location and site of origin of the different projections. Because vasopressin
expression is steroid- dependent in the BNST and medial amygdala of the mouse, we were able
to use hormonal manipulation to determine which brain regions likely receive vasopressin
innervation from these nuclei. Male and female mice were gonadectomized or sham operated,
and vasopressin-immunoreactivity was examined in brains collected 15 weeks following surgery.
Castration nearly eliminated vasopressin-immunoreactivity in fibers and terminals in numerous
areas, many of which are part of, or associated with the limbic loop, suggesting they originate in
the BNST or medial amygdala (e.g., lateral septum, ventral striatum and pallidum, bed nucleus
of the stria terminalis, amygdala, lateral habenular nucleus, and mediodorsal nucleus thalamus).
In contrast, some brain areas such as the paraventricular nucleus of the thalamus and
dorsomedial hypothalamus retained both fiber and terminal staining suggesting different sources
of innervation. Evaluation of vasopressin innervation of the limbic system may shed light on the
role that vasopressin plays in social behavior.
Disclosures: B.D. Rood, None; G.J. de Vries, None.
Poster
279. Steroids and Plasticity I
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm