Central nervous system mechanisms of ventilatory acclimatization to hypoxia.
Ventilatory acclimatization to hypoxia is the time-dependent increase in ventilation that occurs with chronic exposure to hypoxia. Despite decades of research, the physiological mechanisms that increase the hypoxic ventilatory response during chronic hypoxia are not well understood. This review focuses on adaptations within the central nervous system (CNS) that increase the hypoxic ventilatory response. Although an increase in CNS responsiveness had been proposed many years ago, only recently has strong experimental evidence been provided for an increase in the CNS gain in the rat, which has proved to be a good model of VAH in humans. Within the CNS, several neuroanatomical sites could be involved as well as changes in various neurotransmitters, neuromodulators or signalling mechanisms within any of those sites. Lastly, adaptations within the CNS could involve both direct effects of decreased P(O(2)) and indirect effects of increased afferent nerve activity due to chronic stimulation of the peripheral arterial chemoreceptors.
Powell
F L
FL
Physiology Division, Department of Medicine 0623A, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0623, USA. fpowell@ucsd.edu
Huey
K A
KA
Dwinell
M R
MR
D000064:Acclimatization / Q000502:physiology; D000818:Animals; D002490:Central Nervous System / Q000503:physiopathology*; D002908:Chronic Disease; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D008959:Models, Neurological; D018377:Neurotransmitter Agents / Q000502:physiology; D051381:Rats; D012143:Respiratory Physiological Phenomena; D015398:Signal Transduction
D018377:Neurotransmitter Agents