Expression of metabotropic glutamate receptor mRNAs in the human spinal cord: implications for selective vulnerability of spinal motor neurons in amyotrophic lateral sclerosis

To elucidate the relevance of metabotropic glutamate receptors (mGluRs) to the selective vulnerability of motor neurons in the spinal cord in patients with amyotrophic lateral sclerosis (ALS), we investigated the distribution of mRNAs coding mGluR1-5 in the normal human spinal cord. The mRNAs for mG luR1, 4 and 5 were observed in the spinal gray matter, whereas mG1uR2 mRNA was absent in the spinal cord and mGluR3 mRNA was displayed only on glial c ells in the white matter. Signals for mGluR1 and mGluR5 were enriched in th e dorsal horn, while mGluR4 mRNA was abundant in the ventral horn. Since ag onists to group I mGluRs (mGluR 1 and 5) have been demonstrated to have neu roprotective effects on spinal motor neurons, less expression of mRNAs codi ng mGluR1 and mGluR5 in the ventral horn than in the dorsal horn may be imp licated in the selective susceptibility of spinal motor neurons in ALS. (C) 2001 Elsevier Science B.V. All rights reserved.