α-Estradiol is an endogenous ligand for estrogen receptors ERα (Ki = 0.2 nM) and ERβ (Ki = 1.2 nM). Studies indicate that α-Estradiol is a short acting estrogen which only forms complexes with estrogen ligand receptors for a short period of time. These studies suggest that α-estradiol is beneficial in studying the affects caused by the MAPK signaling cascade such as cell division, neuronal differentiation, and neuronal survival in the developing brain. Furthermore, α-estradiol inhibits the influx of calcium in human aortic smooth muscle cells.