Human galanin is a 30-amino acid neuropeptide and galanin (GAL) receptor agonist.1,2,3,4 It inhibits forskolin-induced cAMP production in HEK293E cells expressing recombinant human GAL1 receptors (EC50 = 0.031 nM) and stimulates inositol phosphate accumulation in CHO cells expressing recombinant human GAL2 receptors (EC50 = 12.3 nM).1,2 Human galanin induces contractions in isolated rat longitudinal fundus strips with an EC50 value of 13.8 nM.3 Intrathecal administration of human galanin (3, 10, and 30 nmol/animal) reduces paw licking and flinching in the second, but not first, phase of the formalin test in rats.4
1.Fitzgerald, L.W., Patterson, J.P., Conklin, D.S., et al.Pharmacological and biochemical characterization of a recombinant human galanin GALR1 receptor: Agonist character of chimeric galanin peptidesJ. Pharmacol. Exp. Ther.287(2)448-456(1998) 2.Borowsky, B., Walker, M.W., Huang, L.Y., et al.Cloning and characterization of the human galanin GALR2 receptorPeptides19(10)1771-1781(1998) 3.Schmidt, W.E., Kratzin, H., Eckart, K., et al.Isolation and primary structure of pituitary human galanin, a 30-residue nonamidated neuropeptideProc. Natl. Acad. Sci. USA88(24)11435-11439(1991) 4.Hua, X.-Y., Hayes, C.S., Hofer, A., et al.Galanin acts at GalR1 receptors in spinal antinociception: Synergy with morphine and AP-5J. Pharmacol. Exp. Ther.308(2)574-582(2004)