CELLULAR ADAPTIVE RESPONSES TO LOW-OXYGEN TENSION - APOPTOSIS AND RESISTANCE

Oxygen plays such a critical role in the central nervous system that a specialized mechanism of oxygen delivery to neurons is required. Redu ced oxygen tension, or hypoxia, may have severe detrimental effects on neuronal cells. Several studies suggest that hypoxia can induce cellu lar adaptive responses that overcome apoptotic signals in order to min imize hypoxic injury or damage. Adaptive responses of neuronal cells t o hypoxia may involve activation of various ion channels, as well as i nduction of specific gene expression. For example, ATP sensitive K+ ch annels are activated by hypoxia in selective neuronal cells, and may p lay a role in cell survival during hypoxia/anoxia. Additionally, hypox ia-induced c-Jun, bFGF and NGF expression appear to be associated with prevention (or delay) of neuronal cell apoptosis. In this paper, thes e adaptive responses to hypoxia in neuronal cells are discussed to exa mine the possible role of hypoxia in pathophysiology of diseases.