Galanin Receptor Antibodies

The galanin receptor family comprises three class A G protein-coupled receptors, GAL₁, GAL₂, and GAL₃, encoded by GALR1, GALR2, and GALR3, respectively. All three respond to the endogenous neuropeptide galanin, while spexin activates GAL₂ and GAL₃. GAL₁ and GAL₃ couple predominantly to Gi/o, inhibiting adenylyl cyclase, whereas GAL₂ preferentially engages Gq/11 to activate phospholipase C and mobilize intracellular calcium. These receptors have distinct distributions in the central and peripheral nervous systems, including regions involved in memory, stress responses, feeding, and pain processing. Experimental studies implicate GAL₁ in inhibition of neurotransmitter release and GAL₂ in neuronal survival and plasticity, while GAL₃ remains less extensively characterized. Agonist-induced internalization varies by subtype and ligand, with galanin generally producing stronger GAL₂ internalization than spexin in recombinant systems. The selective GAL₃ antagonist HT-2157 has undergone phase 1/2 testing in healthy volunteers and patients with major depressive disorder. No galanin receptor-selective drug is currently approved for therapeutic use.