The mechanisms of the action of sex steroid hormones on the nervous system are related to both classical, intracellularly mediated effects and non-classical membrane effects due to binding to membrane receptors. Some steroids are capable of inducing rapid neurotransmitter-like effects, similar to those of dopamine or glutamate that alter the activity of neuronal systems via different types of receptors. The neuroactive steroids are endogenous neuromodulators synthesized in the brain and rapidly affecting neuronal excitability. Sex steroids exert many pleiotropic effects in the nervous system: they modulate main neurotransmitter systems, promote the viability of neurons, play an important role in myelination, and influence cognitive processes. Estradiol protects neurons from excitotoxic damage and increases neuronal survival. Progesterone stimulates neurological and functional recovery. Androgens also exhibit a wide array of neuroprotective effects in motoneurons, including supporting cell survival, axonal regeneration, and dendritic maintenance. Despite the considerable increase of sex hormones and neurosteroids research in recent years and the ongoing discovery of biochemical mechanisms of action, their role in neurodegenerative processes remains not well determined.
Part of the book: Sex Hormones in Neurodegenerative Processes and Diseases