Peripheral kynurenine metabolism in focal dystonia.
Substantial evidence indicates that neuroactive kynurenine metabolites play a role in the normal physiology of the human brain, and are involved in the pathology of neurodegenerative disorders such as Parkinson's disease and Huntington's disease. A side-arm product of the pathway, kynurenic acid (KYNA), which is synthesized by the irreversible transamination of kynurenine (KYN) by kynurenine aminotransferases (KAT I and KAT II), is an excitatory amino acid receptor antagonist. In the present study, we measured the level of KYNA and the activities of the biosynthetic enzyme isoforms KAT I and KAT II in the plasma and in the erythrocytes (RBCs) of patients with cervical dystonia or blepharospasm and in age-matched controls. The KAT I and KAT II activities were significantly lower in the plasma of the patients in both subgroups. In the RBCs, only the KAT I activity was elevated significantly. The KYNA concentration was unchanged in both type of patients. These data support the contribution of an altered kynurenine metabolism to the pathogenesis of focal dystonia.
Hartai
Zsuzsanna
Z
Department of Neurology, University of Szeged, Szeged, Hungary.
Klivenyi
Peter
P
Janaky
Tamas
T
Penke
Botond
B
Dux
Laszlo
L
Vecsei
Laszlo
L
D000123:Acetyltransferases / Q000097:blood; D000328:Adult; D001764:Blepharospasm / Q000378:metabolism; D016022:Case-Control Studies; D020821:Dystonic Disorders / Q000209:etiology* / Q000378:metabolism*; D004912:Erythrocytes / Q000737:chemistry; D005260:Female; D006801:Humans; D007736:Kynurenic Acid / Q000032:analysis / Q000097:blood; D007737:Kynurenine / Q000378:metabolism*; D008297:Male; D008875:Middle Aged
D007737:Kynurenine; D000123:Acetyltransferases; C103393:kinamycin acetyltransferase I; D007736:Kynurenic Acid