IMMUNOCYTOCHEMICAL LOCALIZATION OF THE MGLUR1-ALPHA METABOTROPIC GLUTAMATE-RECEPTOR IN THE DORSAL COCHLEAR NUCLEUS

We demonstrate that the metabotropic glutamate receptor mGluR1 alpha i s enriched in two interneuron cell populations in the dorsal division of the cochlear nucleus. Electron microscopic analysis confirms that m GluR1 alpha immunoreactivity is concentrated in the dendritic spines o f cartwheel cells and in dendrites of the recently described unipolar brush cells. The cartwheel cells, which have many similarities to the Purkinje cells of the cerebellum, participate in a local neuronal circ uit that modulates the output of the dorsal cochlear nucleus. Immunost ained unipolar brush cells were observed in granule cell regions of th e cochlear nucleus and the vestibulocerebellum. The presence of analog ous cell types with similar patterns of immunolabeling in the cerebell um and in the dorsal cochlear nucleus suggests that a shared but as ye t unknown mode of processing may occur in both structures. (C) 1996 Wi ley-Liss, Inc.