Skip to main content
PMC home page
The Journal of Physiology logoLink to The Journal of Physiology
. 1976 Mar;255(3):701–714. doi: 10.1113/jphysiol.1976.sp011304

The effect of hypercapnia on a blood-brain barrier mechanism in foetal and new-born sheep.

C A Evans, J M Reynolds, M L Reynolds, N R Saunders
PMCID: PMC1309275  PMID: 1263141

Abstract

1. The effect of marked hypercapnia (arterial PCO2 100 mmHg), nonrespiratory acidosis (pH 6-95-7-15) or hypoxia (arterial PO2 10-15 mmHg) upon penetration of labelled sucrose from blood into brain and c.s.f. has been investigated in exteriorized foetal sheep and new-born lambs. 2. In hypercapnia there was a consistent increase in c.s.f./plasma sucrose ratio after 90 min I.V. sucrose to four to five times control. Brain/plasma sucrose ratios were more variable. Usually there was an increase (up to three-and-a-half-times control); sometimes there was no change or even a decrease. The effect of hypercapnia on sucrose penetration was reversible. 3. Hypercapnia reduced c.s.f. secretion rate to approximately half the control value. Hypercapnia also caused a decrease in brain extracellular space. 4. Non-respiratory acidosis did not affect sucrose penetration. Hypoxia caused a decrease in brain/plasma sucrose ratio. 5. It is concluded that hypercapnia can cuase an increase in cerebral vascular permeability to sucrose in foetal and new-born sheep. Some possible mechanisms are discussed.

Full text

PDF
701

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Bradbury M. W., Crowder J., Desai S., Reynolds J. M., Reynolds M., Saunders N. R. Electrolytes and water in the brain and cerebrospinal fluid of the foetal sheep and guinea-pig. J Physiol. 1972 Dec;227(2):591–610. doi: 10.1113/jphysiol.1972.sp010049. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Bratlid D., Fog J. The binding capacity of human albumin for bilirubin and its significance in the significance in the pathogenesis of kernicterus. Scand J Clin Lab Invest. 1970 May;25(3):257–261. doi: 10.3109/00365517009046203. [DOI] [PubMed] [Google Scholar]
  3. CLEMEDSON C. J., HARTELIUS H., HOLMBERG G. The influence of carbon dioxide inhalation on the cerebral vascular permeability to trypan blue (the blood-brain barrier). Acta Pathol Microbiol Scand. 1958;42(2):137–149. doi: 10.1111/j.1699-0463.1958.tb03178.x. [DOI] [PubMed] [Google Scholar]
  4. Cameron I. R., Davson H., Segal M. B. The effect of hypercapnia on the blood-brain barrier to sucrose in the rabbit. Yale J Biol Med. 1969 Dec;42(3-4):241–247. [PMC free article] [PubMed] [Google Scholar]
  5. Cutler R. W., Barlow C. F. The effect of hypercapnia on brain permeability to protein. Arch Neurol. 1966 Jan;14(1):54–63. doi: 10.1001/archneur.1966.00470070058007. [DOI] [PubMed] [Google Scholar]
  6. Davson H., Welch K. The permeation of several materials into the fluids of the rabbit's brain. J Physiol. 1971 Oct;218(2):337–351. doi: 10.1113/jphysiol.1971.sp009621. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Evans C. A., Reynolds J. M., Reynolds M. L., Saunders N. R., Segal M. B. The development of a blood-brain barrier mechanism in foetal sheep. J Physiol. 1974 Apr;238(2):371–386. doi: 10.1113/jphysiol.1974.sp010530. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. HARPER A. M., GLASS H. I., GLOVER M. M. Measurement of blood flow in the cerebral cortex of dogs, by the clearance of krypton-85. Scott Med J. 1961 Jan;6:12–17. doi: 10.1177/003693306100600103. [DOI] [PubMed] [Google Scholar]
  9. Hochwald G. M., Malhan C., Brown J. Effect of hypercapnia on CSF turnover and blood-CSF barrier to protein. Arch Neurol. 1973 Mar;28(3):150–155. doi: 10.1001/archneur.1973.00490210030002. [DOI] [PubMed] [Google Scholar]
  10. LENDING M., SLOBODY L. B., MESTERN J. Effect of hyperoxia, hypercapnia, and hypoxia on blood-cerebrospinal fluid barrier. Am J Physiol. 1961 May;200:959–962. doi: 10.1152/ajplegacy.1961.200.5.959. [DOI] [PubMed] [Google Scholar]
  11. Mann L. I. Developmental aspects and the effect of carbon dioxide tension on fetal cephalic blood flow. Exp Neurol. 1970 Jan;26(1):136–147. doi: 10.1016/0014-4886(70)90095-6. [DOI] [PubMed] [Google Scholar]
  12. Novy M. J., Parer J. T., Behrman R. E. Equations and nomograms for blood-oxygen dissociation curves in adult and fetal macaques. J Appl Physiol. 1969 Mar;26(3):339–345. doi: 10.1152/jappl.1969.26.3.339. [DOI] [PubMed] [Google Scholar]
  13. OPPELT W. W., MAREN T. H., OWENS E. S., RALL D. P. EFFECTS OF ACID-BASE ALTERATIONS ON CEREBROSPINAL FLUID PRODUCTION. Proc Soc Exp Biol Med. 1963 Oct;114:86–89. doi: 10.3181/00379727-114-28593. [DOI] [PubMed] [Google Scholar]
  14. Purves M. J., James I. M. Observations on the control of cerebral blood flow in the sheep fetus and newborn lamb. Circ Res. 1969 Dec;25(6):651–667. doi: 10.1161/01.res.25.6.651. [DOI] [PubMed] [Google Scholar]
  15. Romanes G. J. The prenatal medullation of the sheep's nervous system. J Anat. 1947 Jan;81(Pt 1):64–81. [PMC free article] [PubMed] [Google Scholar]

Articles from The Journal of Physiology are provided here courtesy of The Physiological Society

RESOURCES