Abstract
Chronic exposure to moderate hypoxia is associated with considerable remodeling of the cerebral microvascular network. In rats exposed to hypobaric (0.5 ATM) hypoxia, cortical microvessel density increases to 171% of controls within the first week. Peak density is reached within two weeks. The increase in hematocrit follows a similar time course. Although the hemodynamic acclimation appears to complete after two weeks, levels of cortical metabolites, obtained after three weeks of exposure, suggest O2 insufficiency at rest. Increased lactate and slightly decreased glycogen concentrations within the brain, along with increased glucose consumption are consistent with an increased dependence on anaerobic glycolysis for energy production. Whatever the production mechanisms, the restored ATP and phosphocreatine levels indicate the energy demand is being met.
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Harik N., Harik S.I., LaManna J.C. On the Increased Cerebral Vascularity in Hypobaric Hypoxia: Time Course and Reversibity in Adult Rats. JCBFM Vol 15, Suppl. 1:S276, 1995.
Baumann R., Bauer C., and Bartels H. Influence of chronic and acute hypoxia on oxygen affinity and red cell 2,3 diphosphoglycerate of rats and guinea pigs, Resp. Physiol., 11: 135–144, 1971.
Harik S.I., Lust W.D., Jones S.C., Lauro K.L., Pundik S., LaManna J.C., Brain glucose metabolism in hypobaric hypoxia, J. Appl. Physiol. 79:136–140, 1995.
LaManna, J.C., Vendel, L.M. and Farrell, R.M. Brain adaptation to chronic hypobaric hypoxia in rats. J. Appl. Physiol. 72:2238–2243, 1992.
Mironov, V., Hritz, M.A., LaManna, J.C., Hudetz, A.G. and Harik, S.I. Architectural alterations in rat cerebral microvessels after hypobaric hypoxia. Brain Res. 660:73–80, 1994.
Hudetz, A.G., Spaulding, J.G. and Kiani, M.F. Computer simulation of cerebral microhemodynamics. Adv. Exp. Med. Biol. 248:293–304, 1989.
Hawkins, R.A., Mans, A.M. and Davis, D.W. Regional ketone body utilization by rat brain in starvation and diabetes. Am.J.Physiol. 250:169–178, 1986.
Hudetz, A.G., Greene, A.S., Feher, G., Knuese, D.E. and Cowley, A.W.J. Imaging system for three-dimensional mapping of cerebrocortical capillary networks in vivo. Microvasc.Res. 46:293–309, 1993.
Lübbers, D.W. Oxygen Delivery and Microcirculation in the Brain. In: Microcirculation in Circulatory Disorders, edited by Manabe, Zweifach, and Messmer, Tokyo: Springer-Verlag, 1988, p. 33–50.
Haynes, R. Physical basis of the dependence of blood viscosity on tube radius. Am.J.Physiol. 198:1193–1200, 1960.
Whitmore, R. A theory of blood flow in small vessels. J.Appl.Physiol. 22:767–771, 1967.
Blum, J.J., Concentration profiles in and around capillaries. Am. J. Physiol. 198:991–998, 1960.
Musch, T.I., Dempsey, J.A., Smith, C.A., Mitchell, G.S. and Bateman, N.T. Metabolic acids and [H+] regulation in brain tissue during acclimatization to chronic hypoxia. J. Appl. Physiol. 55:1486–1495, 1983.
Siesjo, B.K. and Messeter, K. Factors determining intracellular pH. In: Ion homeostasis of the brain, edited by Siesjo, B.K. and Sorensen, S.C., New York: Academic Press, 1970, p. 244–269.
Johannsson, H. and Siesjo, B.K. CBF and CMRO2 in hypoxia. Acta Physiol.Scand. 93:269–276, 1975.
LaManna, J.C., Light, A.I., Peretsman, S.J. and Rosenthal, M. Oxygen insufficiency during hypoxic hypoxia in rat brain cortex. Brain Res. 293:313–318, 1984.
Connett, R.J., Honig, C.R., Gayeski, T.E.J. and Brooks, G.A. Defining hypoxia: a systems view of VO2, glycolysis, energetics, and intracellular PO2. J. Appl. Physiol. 68:833–842, 1990.
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Lauro, K.L., LaManna, J.C. (1997). Adequacy of Cerebral Vascular Remodeling Following Three Weeks of Hypobaric Hypoxia. In: Nemoto, E.M., et al. Oxygen Transport to Tissue XVIII. Advances in Experimental Medicine and Biology, vol 411. Springer, Boston, MA. https://doi.org/10.1007/978-1-4615-5865-1_47
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DOI: https://doi.org/10.1007/978-1-4615-5865-1_47
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