TDK conference 2008

The septal complex is a part of the limbic system, it has connections with several brain regions, mainly the hypothalamus. The lateral septal nuclei (LS) play an important role in the regulation of several vegetative functions, among others in the neural regulation of food intake. According to earlier research results density changes in the immunocytochemically detectable amount of some orexigenic neuropeptides (neuropeptide Y, galanin, leucin-enkephalin) were measured after partial food deprivation in the lateral septum of male and female rats. Our aim was to study density changes in CART-immunoreactivity induced by partial food deprivation in the lateral septum of male, female and ovariectomized rats.

Young adult male, female and ovariectomized female Wistar rats were used in two groups: control (male: n=3, female: n=4, ovariectomized female: n=4) and fasted (male: n=3, female: n=4, ovariectomized female: n=4) where animals suffered 40 % food deprivation for one week. The brains were removed after 4 % paraformaldehyde perfusion fixation, then 60 m vibratome serial sections were cut from the lateral septal area. Pre-embedding CART-immunocytochemistry was carried out on the free-floating sections. Light microscopic serial sections were then digitally photographed, and the photos were evaluated with computer-assisted densitometry (Scion Image), results were represented on graphs and the Kaleidagraph program and program of VassarStat’s website were used for statistical analysis.

According to our results the detectable amount of CART-immunoreactive elements has decreased significantly in fasted males and females compared to the control animals. The density of CART was slightly reduced after ovariectomy and it has increased in fasted ovariectomized females. This result maybe due to the orexigenic effect of ovariectomia which caused increase in the density of NPY, an orexigenic peptide, therefore the animals were overweight and had a large amount of stored lipids by the start of fasting, compared to control animals.

The density changes of CART-immunoreactive elements induced by food deprivation in the lateral septum prove the important role of lateral septum in food intake.