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Sensitivity of Orexin-A Binding to Phospholipase C Inhibitors, Neuropeptide Y, and Secretin
- Source :
- Biochemical and Biophysical Research Communications. 272:959-965
- Publication Year :
- 2000
- Publisher :
- Elsevier BV, 2000.
-
Abstract
- The binding of [(125)I] orexin-A (Ox-A) to particulates from Chinese hamster ovary (CHO) cells expressing the cloned orexin-A receptor, or from rat forebrain areas, was sensitive to blockers of phosphatidylinositol-specific phospholipase C (PtdIns-PLC) U-73122 and ET-18-OCH(3), little affected by phospholipase A(2) inhibitor quinacrine, and not sensitive to D609, a xanthate inhibitor of phosphatidylcholine-selective PLC. Interaction of the receptor with a PtdIns-PLC was further indicated by a large sensitivity of the binding to Ca(2+). Up to 50% of the binding was sensitive to the G-protein nucleotide site agonist GTP-gamma-S. Ligand attachment to the orexin-A receptor thus depends on an association with both PtdIns-PLC and G-protein alpha-subunits. In all paradigms examined, the binding of [(125)I]orexin-A was competed by human/rat neuropeptide Y (hNPY) and porcine secretin with a potency similar to orexin-A (IC(50) range 30-100 nM). The rank order of potency for NPY-related peptides was hNPY > porcine peptide YY (pPYY) > (Leu(31), Pro(34)) human PYY > human PYY(3-36) > hNPY free acid > human pancreatic polypeptide. Among secretin-related peptides, the rank order of potency was porcine secretin > or = orexin-A > human pituitary adenylate cyclase-activating peptide > orexin-B > porcine vasoactive intestinal peptide. Among opioid peptides, rat beta-endorphin and camel delta-endorphin were much less active than NPY and secretin, and two enkephalins were inactive at 1 microM. In view of high abundance of NPY in forebrain, the above cross-reactivity could indicate a significant contribution of NPY to signaling via orexin-A receptors.
- Subjects :
- Male
Receptors, Neuropeptide
medicine.medical_specialty
Biophysics
Secretin receptor family
CHO Cells
Secretin family
Biology
Binding, Competitive
Biochemistry
Phospholipases A
Receptors, G-Protein-Coupled
Secretin
Rats, Sprague-Dawley
Inhibitory Concentration 50
Phosphoinositide Phospholipase C
Prosencephalon
Orexin Receptors
Cricetinae
Internal medicine
mental disorders
medicine
Animals
Humans
Magnesium
Neuropeptide Y
Enzyme Inhibitors
Opioid peptide
Molecular Biology
Orexins
Phospholipase A
Phospholipase C
Phosphatidylinositol Diacylglycerol-Lyase
Neuropeptides
digestive, oral, and skin physiology
Intracellular Signaling Peptides and Proteins
Cell Biology
Neuropeptide Y receptor
Heterotrimeric GTP-Binding Proteins
Rats
Endocrinology
Guanosine 5'-O-(3-Thiotriphosphate)
Type C Phospholipases
Peptide YY
Calcium
Carrier Proteins
hormones, hormone substitutes, and hormone antagonists
Signal Transduction
Subjects
Details
- ISSN :
- 0006291X
- Volume :
- 272
- Database :
- OpenAIRE
- Journal :
- Biochemical and Biophysical Research Communications
- Accession number :
- edsair.doi.dedup.....31b5d67e2987192f605d6a1aca16dd0a