Abstract
This study was carried out to investigate the morphological changes of the oxytocin secreting neurons in age-related rat hypothalamus by means of immunohistochemistry. The experimental group was 20 aged female rats (Sprague-Dawley, 25~30 months), and the control group was 10 adult female rats (10 months). All animals were perfused transcardially with 4% paraformaldehyde-lysine-periocdate(PLP), and serial transverse brain sections($30{\mu}m$) were prepared by means of cryotome, and were stained with rabbit anti-oxytocin antisera immunohistochemically, using the free floating method and avidin-viotin peroxidase complex. The results were as followings. 1. The immunostained oxytocin secreting neurons were located at the paraventricular nucleus and supraoptic nucleus of age-related rat hypothalamus chiefly. 2. The numbers of oxytocin secreting neurons decreased at the paraventricular nucleus and supraoptic nucleus of age-related rat hypothalamus(p<0.01) 3. The oxytocin secreting neurons of age-related rat hypothalamus immunostained less than those of the adult rat hypothalamus, and the paraventricular nucleus immunostained greater than supraoptic nucleus in age-related rat. 4. The numbers and expansion of dendrite and axonal varicosities decreased in the age-related rat hypothalamus greatly.