Molecular Characterization and Expression of Cloned Human Galanin Receptors GALR2 and GALR3

摘要: Abstract: Galanin is a 29- or 30-amino acid peptide with wide-ranging effects on hormone release, feeding behavior, smooth muscle contractility, and somatosensory neuronal function. Three distinct galanin receptor (GALR) subtypes, designated GALR1, 2, 3, have been cloned from the rat. We report here cloning of human GALR2 GALR3 genes, an initial characterization their pharmacology respect to radioligand binding signal transduction pathways, profile expression in brain peripheral tissues. Human show, respectively, 92 89% amino sequence identity rat homologues. Radioligand studies 125I-galanin show that recombinant binds high affinity (KD = 0.3 nM). less (IC50 12 nM for porcine 75 galanin). was shown couple phospholipase C elevation intracellular calcium levels as assessed by aequorin luminescence HEK-293 cells Xenopus melanophore pigment aggregation dispersion assays, contrast GALR1 GALR3, which predominantly through inhibition adenylate cyclase. mRNA shows wide distribution (mammillary nuclei, dentate gyrus, cingulate posterior hypothalamic, supraoptic, arcuate nuclei), restricted tissue highest detected small intestine. In comparison, whereas expressed many areas brain, there abundant primary olfactory cortex, tubercle, islands Calleja, hippocampal CA regions Ammon's horn, gyrus. highly testis detectable adrenal gland pancreas. The genes 3 were localized chromosomes 17q25 22q12.2–13.1, respectively.