Novel role for reactive oxygen species as amplifiers of intermittent hypoxia. Focus on 'Reactive oxygen species mediate central cardiorespiratory network responses to acute intermittent hypoxia'.

摘要

Hypoxia (i.e., decreased O_2 availability) is a pervasive physiological stimulus that profoundly affects biological systems. Systemic responses to acute hypoxia occur within seconds and are mediated entirely by reflexes originating from peripheral chemo-receptors especially the carotid bodies. Cellular mechanisms associated with acute hypoxia involve inhibition of certain classes of K~+ channels leading to release of variety of neurotransmitters/ modulators in the chemo-reflex pathway. On the other hand, chronic hypoxia persisting for several hours to days leads to phenotypic re-modeling and adaptation of physiological systems, which require activation of transcription factors most notably the hypoxic inducible factor-1 (HIF-1) (Semenza 2000). In work published in this issue of the Journal of Neurophysiology, Grif-fioen et al. (p. 2059-2066) demonstrate fundamental mechanistic differences in the effects of continuous versus intermittent hypoxia (IH), the most frequent form of hypoxic challenge to whichhumans are exposed.