Astrocytes and Development of Neuroendocrine Circuits

Abstract

Astrocytes, one of the most abundant cell types in the hypothalamus, perform a myriad of functions throughout all stages of development. Radial glia, astroglia-like progenitor cells, are fundamental for neurogenesis, neuronal migration, axon extension, and synaptic formation throughout the brain. These progenitor cells also give rise to mature astrocytes, which are essential for the proper functioning of the brain at all ages. In the hypothalamus, astrocytes play an important role in all neuroendocrine systems. Together with tanycytes, specialized glial cells surrounding the third ventricle of the hypothalamus, astrocytes maintain some of their developmental potential into adulthood, including their progenitor com-petence and ability to modulate synaptic plasticity. In this chapter, we will address what is known regarding the role of astrocytes in hypothalamic develop-ment. We will briefly cover some of the functions that astrocytes perform in specific neuroendocrine systems, as well as how the maintenance of certain developmental capacities during later stages of life is fundamental for systemic adaptation and homeostatic control. Although the roles of astrocytes in neuroen-docrine control have received increasing attention in recent years, there is still much to be learned regarding these fascinating cells. Identification of functional astrocytic populations with specific markers will allow these cells to be targeted and more easily manipulated, so that we can begin to learn details about how astroglia participate in the development of specific hypothalamic circuits.