Effect of dexamethasone treatment on maturational changes in the NMDA receptor in sheep brain

J. E. McGowan, G. Sysyn, K. H. Petersson, G. B. Sadowska, O. P. Mishra, M. Delivoria-Papadopoulos, B. S. Stonestreet

    Research output: Contribution to journalArticle

    Abstract

    The objective of the present study was to examine the effect of antenatal or postnatal treatment with corticosteroids on the NMDA receptor, one of the mediators of both normal brain development and hypoxic-ischemic injury, by determining the characteristics of the receptor MK-801 binding site in untreated and corticosteroid-treated fetal and newborn lambs. 3H-MK-801 binding was performed in cerebral cortical cell membranes from fetal sheep at 88, 120, and 136 d gestation (term = 150 d), and from 5-d-old lambs and adult ewes. Animals were randomized to receive dexamethasone [fetuses: 6 mg, i.m. every 12 hr for four doses to mother; lambs: 0.01 mg/kg (low dose) or 0.25 mg/kg (high dose) every 12 hr for four doses] or placebo. During development, B(max) (apparent number of receptors) increased, reaching a maximum in 5-d-old lambs (p <0.05) and decreasing in the adult brain. K(d) (dissociation constant) did not change, suggesting that receptor affinity was not altered during maturation. Dexamethasone treatment had no effect on MK-801 binding in the fetus or adult, but in lambs was associated with a significant decrease in B(max) from 2.17 ± 0.18 pmol/mg protein in placebo-treated animals to 1.65 ± 0.8 and 1.62 ± 0.07 pmol/mg protein in low-dose and high-dose animals, respectively. Affinity for 3H-MK-801 decreased 20% after dexamethasone treatment in lambs only (p <0.05). Thus, dexamethasone treatment appears to modify the NMDA receptor only during a specific period of brain development.

    Original languageEnglish (US)
    Pages (from-to)7424-7429
    Number of pages6
    JournalJournal of Neuroscience
    Volume20
    Issue number19
    StatePublished - Oct 1 2000

    Fingerprint

    Dizocilpine Maleate
    N-Methyl-D-Aspartate Receptors
    Dexamethasone
    Sheep
    Brain
    Adrenal Cortex Hormones
    Fetus
    Placebos
    Therapeutics
    Proteins
    Binding Sites
    Cell Membrane
    Pregnancy
    Wounds and Injuries

    Keywords

    • Brain development
    • Corticosteroids
    • Glutamate receptors
    • NMDA
    • Receptor binding
    • Sheep

    ASJC Scopus subject areas

    • Neuroscience(all)

    Cite this

    McGowan, J. E., Sysyn, G., Petersson, K. H., Sadowska, G. B., Mishra, O. P., Delivoria-Papadopoulos, M., & Stonestreet, B. S. (2000). Effect of dexamethasone treatment on maturational changes in the NMDA receptor in sheep brain. Journal of Neuroscience, 20(19), 7424-7429.

    Effect of dexamethasone treatment on maturational changes in the NMDA receptor in sheep brain. / McGowan, J. E.; Sysyn, G.; Petersson, K. H.; Sadowska, G. B.; Mishra, O. P.; Delivoria-Papadopoulos, M.; Stonestreet, B. S.

    In: Journal of Neuroscience, Vol. 20, No. 19, 01.10.2000, p. 7424-7429.

    Research output: Contribution to journalArticle

    McGowan, JE, Sysyn, G, Petersson, KH, Sadowska, GB, Mishra, OP, Delivoria-Papadopoulos, M & Stonestreet, BS 2000, 'Effect of dexamethasone treatment on maturational changes in the NMDA receptor in sheep brain', Journal of Neuroscience, vol. 20, no. 19, pp. 7424-7429.
    McGowan JE, Sysyn G, Petersson KH, Sadowska GB, Mishra OP, Delivoria-Papadopoulos M et al. Effect of dexamethasone treatment on maturational changes in the NMDA receptor in sheep brain. Journal of Neuroscience. 2000 Oct 1;20(19):7424-7429.
    McGowan, J. E. ; Sysyn, G. ; Petersson, K. H. ; Sadowska, G. B. ; Mishra, O. P. ; Delivoria-Papadopoulos, M. ; Stonestreet, B. S. / Effect of dexamethasone treatment on maturational changes in the NMDA receptor in sheep brain. In: Journal of Neuroscience. 2000 ; Vol. 20, No. 19. pp. 7424-7429.
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