Calcitonin receptor-like receptor is expressed on gastrointestinal immune cells

Background/Aims: Pharmacological and morphological studies suggest
that the gut mucosal immune system and local
neuropeptide-containing neurones interact. We aimed to determine
whether gut immune cells are targets for calcitonin gene-related
peptide (CGRP), which has potent immune regulatory properties.
Methods: Using density gradient centrifugation, rat lamina propria
mononuclear cells (LP-MNCs) and intra-epithelial lymphocytes (IELs)
were isolated. RT-PCR was employed for the detection of mRNA of rat
calcitonin receptor-like receptor (CRLR), which is considered to
represent the pharmacologically defined CGRP receptor-1 subtype, as
well as mRNA of the receptor activity-modifying proteins, which are
essential for CRLR function and determine ligand specificity. A
radioreceptor assay was employed for the detection of specific CGRP
binding sites. Results: RT-PCR and DNA sequencing showed that
LP-MNCs and IELs express CRLR. Incubation of isolated LP-MNCs with
radiolabelled alphaCGRP revealed the existence of specific binding
sites for CGRP. Conclusion: These novel data indicate that mucosal
immune cells of the rat gut are a target for CGRP and provide
significant evidence that CGRP functions as an immune regulator in
the gut mucosa. Copyright (C) 2002 S. Karger AG, Basel.