Cellular localization of metabotropic glutamate receptors mGluR1, 2/3, 5 and 7 in the main and accessory olfactory bulb of the rat

The cellular localization of metabotropic glutamate receptors (mGluRs) (mGl uR1 alpha, 2/3, 5a and 7) in the main and accessory olfactory bulb (MOB and AOB) of adult rats was compared by using affinity purified polyclonal anti bodies directed to their C-termini. mGluR1 alpha and mGluR5a immunoreactivi ties were located in comparable structures of the MOB and AOB with differen t levels of intensity. mGluR5a reactivity was high in the AOB. mGluR2/3 sho wed a different pattern of expression in the MOB compared to that observed in the AOB; the periglomerular region of the MOB was strongly stained, but in the AOB it was the mitral/tufted cell layer that was intense. The mitral cell bodies in the MOB were strongly immunoreactive for mGluR7. These diff erences in the distribution of mGluRs in the MOB and AOB may reflect differ ences in synaptic transmission and sensitivity to neuromodulation in the tw o systems. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.