Morphology and distribution of hypothalamic peptidergic systems.

Neuropeptides participate in the regulation of numerous hypothalamic functions that are aimed for sustaining the homeostasis of the organism. These neuropeptides can act in two different levels. They can influence the release of hormones from the adenohypophysis via the portal circulation; in addition, they can act as neurotransmitters/neuromodulators modulating the functioning of numerous hypothalamic neurotransmitter systems. Indeed, most of these peptidergic systems form a complex network in the infundibular and periventricular nuclei of the human hypothalamus, communicating with each other by synaptic connections that may control fundamental physiologic functions. In the present chapter, we provide an overview of the distribution of neuropeptides in the human hypothalamus using immunohistochemistry and high-resolution, three-dimensional mapping.