Immuno-localization of kynurenine aminotransferase (KAT) in the rat medulla and spinal cord.
In the mammalian brain, kynurenine aminotransferase (KAT) is pivotal to the synthesis of kynurenic acid, a preferential antagonist at the strychnine-insensitive NMDA-glycine site. As NMDA receptors are involved in autonomic function, we have examined the immunohistochemical localization of KAT in the medulla and spinal cord of the rat. KAT immunoreactivity (KAT-li) was found throughout these areas, in both glia and neurons. Unlike the mainly astrocytic localization in forebrain structures, KAT-li was predominantly neuronal, notably in areas important for blood pressure and heart rate regulation: ventral medulla, nucleus ambiguus, nucleus of the solitary tract and intramediolateral cell column of the spinal cord. The presence of KAT in these nuclei supports a neuromodulatory role for kynurenic acid in NMDA-mediated autonomic function.
Kapoor
R
R
School of Physiology and Pharmacology, University of New South Wales, Sydney, Australia.
Okuno
E
E
Kido
R
R
Kapoor
V
V
D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000201:enzymology; D008190:Lyases; D008297:Male; D008526:Medulla Oblongata / Q000166:cytology / Q000201:enzymology*; D009457:Neuroglia / Q000166:cytology / Q000201:enzymology; D009474:Neurons / Q000166:cytology / Q000201:enzymology; D009928:Organ Specificity; D010296:Parietal Lobe / Q000166:cytology / Q000201:enzymology; D016548:Prosencephalon / Q000166:cytology / Q000201:enzymology; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D017552:Solitary Nucleus / Q000201:enzymology; D013116:Spinal Cord / Q000166:cytology / Q000201:enzymology*; D000637:Transaminases / Q000032:analysis*
D000637:Transaminases; C427605:glutamine - phenylpyruvate transaminase; C021481:kynurenine-oxoglutarate transaminase; D008190:Lyases