Galanin receptors are poorly expressed in murine isolated pancreatic acinar cells but are highly expressed in islet cells

The neuropeptide galanin modulates pancreatic endocrine andexocrine secretion. The galanin receptor (GALR) expressionthroughout the pancreas however is not fully described. ThreeGALRs are known; GALR1, GALR2 and GALR3. We aimed to deter-mine the GALR expression in normal whole mouse pancreas(n=5), acinar and islet cells (n=4 and 5 preparations, respectively).Pancreata were rapidly harvested for acinar and islet cells prepara-tion by standard techniques. Extraction of total RNA used a Trizolprotocol specifically designed for pancreas. The expression ofGALRs mRNA was determined by real-time reverse transcription-polymerase chain reaction with primers designed specifically forthese transcripts. Hypoxanthine phosphoribosyltransferase wasused as a housekeeping gene for normalisation of expression data.In-situ hybridization using locked nucleic acid probes localized themRNA for each GALR in sections of murine pancreas. In whole pan-creas, GALR expression was low. GALR3 showed the highest ex-pression with GALR1 and GALR2 expressed at comparable levels.The GALR expression profile and levels in acinar cells were similarto whole pancreas. In contrast, GALRs were highly expressed and atcomparable levels in islet cells. These findings were supported bymRNA localization studies using in-situ hybridization. We con-clude that GALRs are highly expressed in mouse pancreatic isletscells and poorly expressed in the acinar cells. These data are con-sistent with our finding that galanin does not act directly on acinarcells to modulate amylase secretion.