Endogenous peptide product of human prepro-VIP and analog of porcine PHI-27; potent agonist for the human calcitonin receptor (EC50 = 11 nM). Transgenic mice expressing the human VIP/PHM27 gene in pancreatic β-islets display enhanced glucose-induced insu
β-Endorphin (1-27) is an endogenous peptide that binds to μ-, δ-, and κ-opioid receptors (Kis = 5.31, 6.17, and 39.82 nM, respectively, in COS-1 cells expressing rat receptors). It binds to rat and mouse brain membrane preparations (IC50s = 1.1 and 5.7 nM, respectively) and induces chemotaxis of human monocytes in vitro when used at a concentration of 1 nM. Intracerebroventricular administration of β-endorphin (1-27) increases the latency to tail withdrawal in response to thermal stimulation in mice with a median antinociceptive dose (AD50) of 1,500 pmol per animal. It inhibits antinociception induced by β-endorphin in mice in response to thermal stimuli when administered at a dose of 65 pmol per animal. In rats, β-endorphin (1-27) does not affect drug-associated place preference when administered at doses up to 20 μg, i.c.v., but inhibits β-endorphin-induced place preference when administered at a dose of 10 μg per animal.
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.
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, is a potent and selective antagonist of PACAP 38, outperforming PACAP (6-27) in inhibiting PACAP-27-stimulated pituitary adenylate cyclase.