Effects of postnatal dexamethasone on blood-brain barrier permeability and brain water content in newborn lambs.
| Title: | Effects of postnatal dexamethasone on blood-brain barrier permeability and brain water content in newborn lambs. |
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| Authors: | Sysyn GD; Department of Pediatrics, Women and Infants' Hospital of Rhode Island, Brown University School of Medicine, Providence, Rhode Island 02905, USA.; Petersson KH; Patlak CS; Sadowska GB; Stonestreet BS |
| Source: | American journal of physiology. Regulatory, integrative and comparative physiology [Am J Physiol Regul Integr Comp Physiol] 2001 Feb; Vol. 280 (2), pp. R547-53. |
| Publication Type: | Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S. |
| Language: | English |
| Journal Info: | Publisher: American Physiological Society Country of Publication: United States NLM ID: 100901230 Publication Model: Print Cited Medium: Print ISSN: 0363-6119 (Print) Linking ISSN: 03636119 NLM ISO Abbreviation: Am J Physiol Regul Integr Comp Physiol Subsets: MEDLINE |
| Imprint Name(s): | Original Publication: Bethesda, Md. : American Physiological Society |
| MeSH Terms: | Blood-Brain Barrier/*physiology ; Body Water/*physiology ; Brain/*physiology ; Dexamethasone/*pharmacology; Blood Glucose/metabolism ; Blood Pressure/drug effects ; Blood-Brain Barrier/drug effects ; Brain/drug effects ; Brain/growth & development ; Carbon Dioxide/blood ; Heart Rate/drug effects ; Hydrocortisone/blood ; Oxygen/blood ; Aging ; Animals ; Animals, Newborn ; Body Weight ; Organ Specificity ; Permeability ; Sheep |
| Abstract: | We showed that antenatal corticosteroids reduced blood-brain barrier permeability in fetuses at 60 and 80%, but not 90% of gestation, and decreased brain water content in fetuses. Our objective was to examine the effects of postnatal corticosteroids on regional blood-brain barrier permeability and brain water content in newborn lambs. Three dexamethasone treatment groups were studied in 3- to 5-day-old lambs. A 0.01 mg/kg dose was selected to estimate the amount of dexamethasone that might have reached fetuses via antenatal treatment of ewes in our previous studies. The other doses (0.25 and 0.5 mg/kg) were chosen to approximate those used clinically to treat infants with bronchopulmonary dysplasia. Lambs were randomly assigned to receive four intramuscular injections of dexamethasone or placebo given 12 h apart on days 3 and 4 of age. Blood-brain barrier function was measured with the blood-to-brain transfer constant (K(i)) to alpha-aminoisobutyric acid, brain plasma volume was measured with polyethylene glycol for the calculation of K(i,) and brain water was measured by wet-to-dry tissue weights. Postnatal treatment with corticosteroids did not reduce barrier permeability in newborn lambs. Brain blood volume was higher in the 0.25 and 0.5 mg/kg dose dexamethasone groups than in the placebo group. Brain water content did not differ among the groups. We conclude that postnatal treatment with corticosteroids did not reduce regional blood-brain barrier permeability or brain water content but increased the brain plasma volume in newborn lambs. These findings are consistent with our previous work indicating that barrier permeability is responsive to corticosteroids at 60 and 80% of gestation and brain water regulation at 60% of gestation, but not in near-term fetuses or newborn lambs. |
| Comments: | Comment in: Am J Physiol Regul Integr Comp Physiol. 2002 Feb;282(2):R632-3. doi: 10.1152/ajpregu.2002.282.2.R632.. (PMID: 11817359) |
| Grant Information: | R01-HD-34618 United States HD NICHD NIH HHS |
| Substance Nomenclature: | 0 (Blood Glucose); 142M471B3J (Carbon Dioxide); 7S5I7G3JQL (Dexamethasone); S88TT14065 (Oxygen); WI4X0X7BPJ (Hydrocortisone) |
| Entry Date(s): | Date Created: 20010224 Date Completed: 20010412 Latest Revision: 20200930 |
| Update Code: | 20260130 |
| DOI: | 10.1152/ajpregu.2001.280.2.R547 |
| PMID: | 11208586 |
| Database: | MEDLINE |
Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S.