Pituitary adenylate cyclase-activating peptide (PACAP) (6-27) is a PACAP receptor antagonist with IC50 values of 1,500, 600, and 300 nM, respectively, for rat PAC1, rat VPAC1, and human VPAC2 recombinant receptors expressed in CHO cells. It binds to PACAP receptors on SH-SY5Y and SK-N-MC human neuroblastoma and T47D human breast cancer cells (IC50s = 24.5, 106, and 105 nM, respectively) and inhibits cAMP accumulation induced by PACAP (1-38) (Kis = 457, 102, and 283 nM, respectively, in SH-SY5Y, SK-N-MC, and T47D cells). In vivo, in newborn pigs, PACAP (6-27) (10 μM) inhibits vasodilation of pial arterioles induced by PACAP (1-27) and PACAP (1-38) . It also inhibits PACAP (1-27)-stimulated increases in plasma insulin and glucagon levels and pancreatic venous blood flow in dogs when administered locally to the pancreas at a dose of 500 μg.
Ganglioside GM1is a monosialylated ganglioside and the prototypic ganglioside for those containing one sialic acid residue.1,2It is found in a large variety of cells, including immune cells and neurons, and is enriched in lipid rafts in the cell membrane.3It associates with growth factor receptors, including TrkA, TrkB, and the GDNF receptor complex containing Ret and GFRα, and is required for TrkA expression on the cell surface. Ganglioside GM1interacts with other proteins to increase calcium influx, affecting various calcium-dependent processes, including inducing neuronal outgrowth during differentiation. Ganglioside GM1acts as a receptor for cholera toxin, which binds to its oligosaccharide group, facilitating toxin cell entry into epithelial cells of the jejunum.4,5Similarly, it is bound by the heat-labile enterotoxin fromE. coliin the pathogenesis of traveler's diarrhea.6Ganglioside GM1gangliosidosis, characterized by a deficiency in GM1-β-galactosidase, the enzyme that degrades ganglioside GM1, leads to accumulation of the gangliosides GM1and GA1in neurons and can be fatal in infants.1Levels of ganglioside GM1are decreased in the substantia nigra pars compacta in postmortem brain from patients with Parkinson's disease.3Ganglioside GM1mixture contains a mixture of ovine ganglioside GM1molecular species with primarily C18:0 fatty acyl chain lengths, among various others. [Matreya, LLC. Catalog No. 1544] 1.Kolter, T.Ganglioside biochemistryISRN Biochem.506160(2012) 2.Mocchetti, I.Exogenous gangliosides, neuronal plasticity and repair, and the neurotrophinsCell Mol. Life Sci.62(19-20)2283-2294(2005) 3.Ledeen, R.W., and Wu, G.The multi-tasked life of GM1 ganglioside, a true factotum of natureTrends Biochem. Sci.40(7)407-418(2015) 4.Turnbull, W.B., Precious, B.L., and Homans, S.W.Dissecting the cholera toxin-ganglioside GM1 interaction by isothermal titration calorimetryJ. Am. Chem. Soc.126(4)1047-1054(2004) 5.Blank, N., Schiller, M., Krienke, S., et al.Cholera toxin binds to lipid rafts but has a limited specificity for ganglioside GM1Immunol. Cell Biol.85(5)378-382(2007) 6.Minke, W.E., Roach, C., Hol, W.G., et al.Structure-based exploration of the ganglioside GM1 binding sites of Escherichia coli heat-labile enterotoxin and cholera toxin for the discovery of receptor antagonistsBiochemistry38(18)5684-5692(1999)
Galanin (2-11) amide is a synthetic peptide fragment of the neuropeptide galanin and an agonist of the galanin-2 (GAL2) receptor (EC50= 9.32 nM in a fluorescence imaging plate reader assay).1It selectively binds to the GAL2receptor (IC50= 1.76 nM for the rat receptor) over the GAL1receptor (IC50= 879 nM for the human receptor) but does also bind to the GAL3receptor (Ki= 271 nM for the rat receptor).1,2Intracerebroventricular administration of galanin (2-11) amide (1 nmol/animal) decreases immobility in the forced swim test in rats.3It also reduces the hind paw mechanical pain threshold and increases the hind paw cold sensitivity threshold in rats.1
PACAP (1-38), a novel neuropeptide isolated from the bovine hypothalamus is more active than vasoactive intestinal peptide (VIP) in stimulating adenylate cyclase (EC50=7 nM). PACAP 1-38 (10-9 M) increased substance P (SP), gastrin releasing peptide (GRP),
PACAP (1-27), human, ovine, rat TFA (PACAP 1-27 TFA), an N-terminal fragment of PACAP-38, is an effective PACAP receptor antagonist with IC50 values of 3 nM for rat PAC1, 2 nM for rat VPAC1, and 5 nM for human VPAC2.
PACAP (1-27) (the N-terminal fragment of PACAP-38) is a novel neuropeptides originally isolated from bovine hypothalamus, also found in humans and rats.
PACAP (6-38), human, ovine, rat TFA is a potent PACAP receptor antagonist with IC50 values of 30 nM, 600 nM, and 40 nM for the PACAP type I receptor, PACAP type II receptor VIP1, and PACAP type II receptor VIP2, respectively.
PACAP (6-38), human, ovine, rat, is a potent and selective antagonist of PACAP 38, outperforming PACAP (6-27) in inhibiting PACAP-27-stimulated pituitary adenylate cyclase.
α-Melanocyte-stimulating hormone (α-MSH) is a 13-amino acid peptide hormone produced by post-translational processing of proopiomelanocortin (POMC) in the pituitary gland, as well as in keratinocytes, astrocytes, monocytes, and gastrointestinal cells.1It is an agonist of melanocortin receptor 3 (MC3R) and MC4R that induces cAMP production in Hepa cells expressing the human receptors (EC50s = 0.16 and 56 nM, respectively).2α-MSH (100 pM) reducesS. aureuscolony formation andC. albicansgerm tube formationin vitro.3It inhibits endotoxin-, ceramide-, TNF-α-, or okadaic acid-induced activation of NF-κB in U937 cells.1α-MSH reduces IL-6- or TNF-α-induced ear edema in mice.4It also prevents the development of adjuvant-induced arthritis in rats and increases survival in a mouse model of septic shock. Increased plasma levels of α-MSH are positively correlated with delayed disease progression and reduced death in patients with HIV.1 1.Catania, A., Airaghi, L., Colombo, G., et al.α-melanocyte-stimulating hormone in normal human physiology and disease statesTrends Endocrinol. Metab.11(8)304-308(2000) 2.Miwa, H., Gantz, I., Konda, Y., et al.Structural determinants of the melanocortin peptides required for activation of melanocortin-3 and melanocortin-4 receptorsJ. Pharmacol. Exp. Ther.273(1)367-372(1995) 3.Cutuli, M., Cristiani, S., Lipton, J.M., et al.Antimicrobial effects of a-MSH peptidesJ. Leukoc. Biol.67(2)233-239(2000) 4.Lipton, J.M., Ceriani, G., Macaluso, A., et al.Antiiinflammatory effect of the neuropeptide a-MSH in acute, chronic, and systemic inflammationAnn. N.Y. Acad. Sci.25(741)137-148(1994)