Title: Peripheral Kynurenine Metabolism in Focal Dystonia
Volume: 3
Issue: 3
Author(s): Zsuzsanna Hartai, Peter Klivenyi, Tamas Janaky, Botond Penke, Laszlo Dux and Laszlo Vecsei
Affiliation:
Keywords:
Cervical dystonia, blepharospasm, kynurenine aminotransferase, kynurenic acid, excitotoxicity
Abstract: 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 Parkinsons disease and Huntingtons 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.