Monoclonal antibodies reveal expression of the CGRP receptor in Purkinje cells, interneurons and astrocytes of rat cerebellar cortex

The molecular layer of adult rat cerebellum displays high levels of calcito nin gene-related peptide (CGRP) receptors, but the cellular location of the receptor remains unidentified. In an attempt to reveal the expression site s of these receptors, monoclonal antibodies raised against purified CGRP re ceptors from porcine cerebellar membranes were used in double-immunofluores cence experiments combined with confocal microscopy. PEP-19, a marker that is highly enriched in Purkinje cells (Pc), revealed that CGRP receptors are located in Pc cytoplasm and dendrites, where they label small puncta somet imes arranged in a row along the course of the dendrite itself. CGRP recept ors were also located in inhibitory interneurons. Furthermore, as shown by double-labeling experiments with GFAP, CGRP receptor-IR labeled Golgi epith elial cells and their radial fibers (Bergmann fibers), as well as astrocyti c processes encircling Pc somata. The simultaneous presence of CGRP recepto rs in Purkinje cells and in the glial cells that heavily enshroud Purkinje cells allows us to hypothesize that these receptors may be involved in neur on-glia interactions influencing neuronal activity. NeuroReport 9: 3755-375 9 (C) 1998 Lippincott Williams & Wilkins.