Neuroglobin is a newly discovered member of the hemoglobin superfamily that is primarily expressed in the brain of humans and other vertebrates. It is an O₂-binding protein localized to cerebral neurons of vertebrates, including humans. Its physiological role is unknown but, like hemoglobin, myoglobin, and cytoglobin/histoglobin, it may transport O₂, detoxify reactive oxygen species, or serve as a hypoxia sensor.Neuroglobin is a member of the vertebrate globin family involved in cellular oxygen homeostasis. It is an intracellular hemoprotein expressed in the central and peripheral nervous system, cerebrospinal fluid, retina and endocrine tissues. Italian researchers suggest that neuroglobin is more likely to usher in nitric oxide to protect neuron survival and recovery in areas where oxygen supply is reduced.