1. ¹Department of Diagnostic Radiology, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
2. ²Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA

Correspondence: Dr GMI Chowdhury, Department of Diagnostic Radiology, Magnetic Resonance Research Center, Yale University School of Medicine, TAC-MRRC, N144, PO Box 208043, 300 Cedar Street, New Haven, CT 6510, USA. E-mail: golam.chowdhury@yale.edu

Received 19 February 2008; Revised 19 June 2008; Accepted 20 June 2008; Published online 16 July 2008.

Abstract

Riluzole is believed to modulate glutamatergic function by reducing glutamate release and facilitating astroglial uptake. We measured ¹³C labeling in metabolites in prefrontal cortex and hippocampus during a 10 mins infusion of [1-¹³C]glucose in urethane anesthetized rats treated with riluzole (21 days, 4 mg/kg per day, i.p.) or saline. Total and ¹³C concentrations of metabolites were determined in extracts using ¹H-[¹³C] NMR spectroscopy. In prefrontal cortex (P<0.05) and hippocampus (P<0.05) riluzole increased ¹³C labeling over saline in glutamate-C4 (to 112% and 130%), GABA-C2 (to 142% and 171%), and glutamine-C4 (to 118% and 233%) without affecting total metabolite levels (P>0.2). Our findings indicate that contrary to expectation chronic riluzole enhanced glucose oxidative metabolism and glutamate/glutamine cycling.