Glutamate transporters in the spinal cord of the wobbler mouse

We studied the role of glutamate excitotoxicity in motor neuron degeneratio n in the wobbler mouse (wr/wr), a model of amyotrophic lateral sclerosis an d spinal muscular atrophies. Choline acetyltransferase (ChAT) activity was decreased in the cervical spinal cord and in the muscles innervated by nerv es originating in this region of wobbler mice, bur, no differences were fou nd in the lumbar spinal cord and in the hindleg muscles. Glial fibrillar ac id protein (GFAP), a marker of reactive gliosis, was significantly higher i n the cervical spinal cord of wobbler mice aged 4 weeks than in controls an d the differences were more marked at 12 weeks; no differences were found i n the lumbar spinal cord. In spite of this selective degeneration of motor neurons (resulting in strong decrease in the neuronal glutamate transporter EAAC1) and reactive gliosis in the cervical spinal cord. the levels of the glial glutamate transporter proteins GLT-1 and GLAST were similar in wobbl er and control mice. Plasma concentrations of excitatory amino acids were n o different at any time examined. Our results exclude the involvement of de crease in glutamate GLT-1 transporter in the motor neuron degeneration in w obbler mice. NeuroReport 12:1815-1820 (C) 2001 Lippincott Williams & Wilkin s.