Pre- and/or post-synaptic localisation of metabotropic glutamate receptor 1α (mGluR1α) 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 was 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 seen in the inner layer of lamina II and the dorsal part of lamina III. In laminae III-X, weakly to moderately stained mGluR1 alpha immunoreactive product 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 lateral and ventral horns, only dendrites of neurons were mGluR1 alpha immunopositive. Some mGluR2/3 immunopositive dendrites were demonstrated in lamina II of the dorsal horn, lateral and ventral horns. In the ventral horn, mGluR2/3 immunopositive axon and axon terminals were demonstrated. Some mGluR2/3 immunopositive astrocytes were also demonstrated in the three areas and their strongly stained processes wrapped around neuronal cell bodies and synapses. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.