DIFFERENTIAL CELLULAR-LOCALIZATION OF 3 SPLICE VARIANTS OF THE MGLUR1METABOTROPIC GLUTAMATE-RECEPTOR IN RAT CEREBELLUM

ANTIBODIES were raised against C-terminal peptides of the splice varia nts a, b and c of the rat mGluR1 metabotropic glutamate receptor. Affi nity purified antibodies each specifically reacting with mGluR1a, mGlu R1b and mGluR1c were used to study the cellular localization of these receptors in rat cerebellum. The mGluR1a antibody strongly labelled Pu rkinje cells at their cells bodies, portions of their dendritic trees and numerous small punctate elements reminiscent of dendritic spines. Also labelled were some stellate, basket, Golgi and Lugaro cells. Gran ule cells were devoid of staining. The mGluR1b antibody strongly label led Purkinje cell bodies and their dendrites at levels which varied wi thin the same lobule of the vermis or the hemispheres. No significant labelling was observed at stellate, basket, Golgi and granule cells, w hile occasionally a fraction of basket cells and cerebellar glomeruli was moderately immunoreactive. The mGluR1c antibody strongly labelled cell bodies and thick principal dendrites of Purkinje cells but not de ndritic spines. Immunonegative Purkinje cells were intermingled with s trongly labelled ones in lobules 4-10, while in lobules 1, 2 and 3, no stained Purkinje cells were detected. The mGluR1c antibody also label led stellate, basket, some Golgi and some Lugaro cells as well as gran ule cells.