Figure 1. Overview of the brain cell types and neuromodulators influenced by estrogens. The ability of estrogens to exert trophic and protective actions depends upon their ability to alter the birth and death of neurons, synaptogenesis, and neuritogenesis. Estradiol influences neurons, astrocytes, and microglia through altering the expression of a broad profile of neurotransmitters and neuropeptides and their receptors, pro- and anti-inflammatory agents, and factors which influence, birth, survival, growth, and maturation of neurons.