ABSTRACT
This chapter aims to relate functional changes in aging with alterations in neuropeptidergic neurons of the human hypothalamus. An age-dependent sex difference was observed in the suprachiasmatic nucleus (SCN): males of 10 to 40 years of age had twice as many vasoactive intestinal peptide neurons in the SCN as females. Interestingly, the number of substance P neurons in the SCN of aged hamsters was increased three to four times compared with adult animals, day and night. The mean profile area of vasopressin cells increased after the age of 80 years, suggesting an increased peptide production from this age onwards. The colocalization of delta sleep-inducing peptide (DSIP) and Luteinizing Hormone-Releasing Hormone (LHRH), as found in the arcuate nucleus of aged human subjects, suggests that DSIP may also play a physiological role in LHRH neurons. LHRH-immunoreactive fibers project to the median eminence, septum, stria terminalis, ventral pallidum, dorsomedial thalamus, olfactory stria, and the anterior olfactory area of the human brain.
