TISSUE-SPECIFIC MESSENGER-RNA EXPRESSION OF A CALCITONIN RECEPTOR-LIKE RECEPTOR DURING FETAL AND POSTNATAL-DEVELOPMENT

The distribution of calcitonin receptor-like receptor (CRLR) mRNA in d eveloping rats was investigated by in situ hybridization. Signals were found in the piriform cortex, the central and basolateral amygdala an d the amygdalostriatal transition area. Among peripheral organs, the C RLR was predominantly expressed in the lung. mRNA expression in blood vessels, liver, midgut, rectum and urethra was restricted to gestation al days 16 and/or 20. The CRLR was thought to be a calcitonin gene-rel ated peptide (CGRP) type 1 receptor (Aiyar et al., J. Biol. Chem., 271 (1996) 11325-11329). This contrasts with previously reported evidence that the CRLR is an orphan receptor with no identifiable interactions with CGRP and other related ligands (Fluhmann et al., Biochem. Biophy s. Res. Commun., 206 (1995) 341-347). In situ hybridization signals ha ve not been detected in the cerebellum and the spleen known to present a high density of CGRP binding sites. The different regional distribu tion of CGRP receptor binding sites and CRLR mRNA implies the latter e ncoding a different CGRP receptor subtype. (C) 1997 Elsevier Science B .V.