Cloning and evaluation of the role of rat GALR-2, a novel subtype of galanin receptor, in the control of pain perception

We have identified a novel subtype of galanin receptor (GALR-2) in rat dorsal root ganglia and spinal cord. The open reading frame of GALR3 is 1116 nucleotides long, encoding a protein of 372 amino acids with a theoretical molecular mass of 40.7 kD, Membranes prepared from stable pools of 293 cells expressing GALR-2, but not wild-type 293 cells, demonstrated high affinity galanin binding sites. Rat galanin and galanin-related peptides M40, C7, M15, and galanin(1-16) effectively competed for binding; peptide C7 demonstrated a lower affinity for rGALR-2, and all these peptides were agonists at rGALR-2 when assessed on a microphysiometer, Studies on the expression of GALR-2 in various tissues by Northern and in situ hybridization analyses suggest a low abundance but wide distribution of GALR-2 mRNA, including several discrete areas in brain and spinal cord and a high abundance in the dorsal root ganglia.