Role of neuroactive steroids in glial cells of the central and peripheral nervous system

The nervous system, like the classical peripheral endocrine glands, e.g. gonads, placenta and adrenal glands, is now considered a steroidogenic organ. Hence, the name “neurosteroids” was coined to indicate properly steroids synthesized in the nervous system. Successively, it was introduced also the term “neuroactive steroids” which includes both the neurosteroids and the classical peripheral hormonal steroids that are metabolized to neuroactive compounds in the nervous system. The neuroactive steroids, via the interactions with the classic and non-classic steroid hormone receptors, exert several effects at the level of the neuronal and non-neuronal cellular compartments. Among these, glial cells, not only represent an important target for the action of neuroactive steroids but are also deputed to synthesize neurosteroids. In this chapter we will summarize the neusteroidogenesis pathways and describe the main functions exerted by neuroactive steroids on these cells.