Capillary NMDA receptors regulate blood-brain barrier function and breakdown.
Polyamines and their regulatory synthetic enzyme ornithine decarboxylase (ODC) have been implicated in blood-brain barrier (BBB) breakdown following cryogenic injury. ODC activation and BBB breakdown are prevented by MK-801, indicating involvement of NMDA receptors. Studies in isolated rat cerebral capillaries supports the presence of NMDA receptors linked to ODC. NMDA (1-50 microM) stimulated capillary uptake of horseradish peroxidase, 2-deoxy-[14C]glucose, and 45 Ca in a receptor-, concentration-, polyamine- and Ca(2+)-dependent manner. We suggest that NMDA receptors may couple capillary transport of nutrients to glutamate-mediated neuronal excitation, and when overestimated disrupt normal BBB function.
Koenig
H
H
Neurology Service, VA Lakeside Medical Center, Chicago IL 60611.
Trout
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Goldstone
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D000818:Animals; D001812:Blood-Brain Barrier / Q000502:physiology*; D001929:Brain Edema / Q000378:metabolism; D002196:Capillaries / Q000502:physiology; D003847:Deoxyglucose / Q000378:metabolism; D005260:Female; D006735:Horseradish Peroxidase; D066298:In Vitro Techniques; D009955:Ornithine Decarboxylase / Q000378:metabolism; D011869:Radioligand Assay; D051381:Rats; D017207:Rats, Sprague-Dawley; D017470:Receptors, Glutamate / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology*
D017470:Receptors, Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; D003847:Deoxyglucose; D006735:Horseradish Peroxidase; D009955:Ornithine Decarboxylase