Pre- and/or post-synaptic localisation of metabotropic glutamate receptor 1 alpha (mGluR1 alpha) and 2/3 (mGluR2/3) in the rat spinal cord

Using immunocytochemical techniques (light and electron microscopy), weakly stained metabotropic glutamate receptor (mGluR) 1 alpha immunoreactivity w as detected in lamina I of the rat spinal cord. Immunoreactivity for mGluR3 /3 was almost undetectable in this lamina and outer lamina II. In lamina II , there was mGluR1 alpha immunoreactivity. Strongly stained mGluR2/3 was se en in the inner layer of lamina II and the dorsal part of lamina III. In la minae III-X, weakly to moderately stained mGluR1 alpha immunoreactive produ ct was demonstrated. Similar staining for mGluR2/3 was also seen in lamina III-VI and in lamina X, but mGluR2/3 immunoreactivities were few in lamina VII-IX. With electron microscopy, mGluR1 alpha immunoreactivity was seen in neuronal cell body and dendrites in lamina II of the dorsal horn. In the l ateral and ventral horns, only dendrites of neurons were mGluR1 alpha immun opositive. Some mGluR2/3 immunopositive dendrites were demonstrated in lami na II of the dorsal horn, lateral and ventral horns. In the ventral horn, m GluR2/3 immunopositive axon and axon terminals were demonstrated. Some mGlu R2/3 immunopositive astrocytes were also demonstrated in the three areas an d their strongly stained processes wrapped around neuronal cell bodies and synapses. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.