Kynurenine aminotransferase in the supratentorial dura mater of the rat: effect of stimulation of the trigeminal ganglion.
Electrical stimulation of the trigeminal ganglion has been widely used as a model of nociception, characterizing migraine. This treatment is known to evoke release of neuropeptides and neurotransmitters from nerve fibers of the dura mater. On the basis of immunocytochemical investigations, we found that under normal conditions, surface membranes of Schwann cells surrounding nerve fibers in the supratentorial dura mater display kynurenine aminotransferase-immunoreaction (KAT-IR); also KAT-IR are the granules of mast cells and the cytoplasms of macrophages (histiocytes). In consequence of stimulation of the trigeminal ganglion, Schwann cells in the dura mater became conspicuously swollen while their KAT-IR decreased considerably; also KAT-IR of mast cells and macrophages decreased significantly. At the same time, nitric oxide synthase (NOS)-IR of nerve fibers in the dura mater increased, suggesting release of nitric oxide (NO), this is known to be involved in NMDA receptor activation leading to vasodilation followed by neurogenic inflammation. Because kynurenic acid (KYNA) is an antagonist of NMDA receptors, we hypothesize that KYNA and its synthesizing enzyme, KAT, may play a role in the prevention of migraine attacks.
Knyihár-Csillik
Elizabeth
E
Department of Clinical Neurology, University Medical School and Neurology Research Group of the Hungarian Academy of Sciences, Szeged, Hungary. knyihar@nepsy.szote.u-szeged.hu
Chadaide
Zoltán
Z
Okuno
Etsuo
E
Krisztin-Péva
Beata
B
Toldi
József
J
Varga
Csaba
C
Molnár
Andor
A
Csillik
Bert
B
Vécsei
László
L
D000818:Animals; D002452:Cell Count / Q000379:methods; D004388:Dura Mater / Q000201:enzymology* / Q000648:ultrastructure; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D007150:Immunohistochemistry / Q000379:methods; D008264:Macrophages / Q000201:enzymology / Q000528:radiation effects / Q000648:ultrastructure; D008297:Male; D008407:Mast Cells / Q000201:enzymology / Q000528:radiation effects / Q000648:ultrastructure; D016253:Microscopy, Immunoelectron / Q000379:methods; D019001:Nitric Oxide Synthase / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012583:Schwann Cells / Q000378:metabolism / Q000648:ultrastructure; D013997:Time Factors; D000637:Transaminases / Q000378:metabolism*; D012668:Trigeminal Ganglion / Q000528:radiation effects*
D019001:Nitric Oxide Synthase; D000637:Transaminases; C021481:kynurenine-oxoglutarate transaminase