title: Neuropeptide Y, an orexigenic hormone, regulates phagocytic activity of lizard splenic phagocytes.
abstract: Present in vitro study in the wall lizard Hemidactylus flaviviridis, for the first time in ectothermic vertebrates, demonstrated the immunoregulatory role of neuropeptide Y (NPY) and its receptor-coupled downstream signaling cascade. NPY inhibited the percentage phagocytosis and phagocytic index of splenic phagocytes. The inhibitory effect of NPY on phagocytosis was completely antagonized by Y(2) and Y(5) receptor antagonists. This suggests that NPY mediated its effect on phagocytosis through Y(2) and Y(5) receptors. Further, NPY receptor-coupled downstream signaling cascade for NPY effect on phagocytosis was explored using the inhibitors of adenylate cyclase (SQ 22536) and protein kinase A (H-89). The SQ 22536/H-89 in a concentration-related manner decreased the inhibitory effect of NPY on phagocytosis. Further, an increase in intracellular cAMP level was observed in response to NPY. Taken together, it can be concluded that NPY via Y(2) and Y(5) receptor-coupled AC-cAMP-PKA pathway downregulated the phagocytic activity of lizard splenic phagocytes.
authors.affiliation: Department of Zoology, University of Delhi, Delhi 110007, India.
authors.forename: Sunil
authors.initials: S
authors.lastname: Kumar
authors.forename: Umesh
authors.initials: U
authors.lastname: Rai
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000067956:Adenylyl Cyclase Inhibitors; D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D019167:Appetite Stimulants / Q000494:pharmacology; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D007546:Isoquinolines / Q000494:pharmacology; D008116:Lizards / Q000378:metabolism*; D009478:Neuropeptide Y / Q000494:pharmacology*; D010586:Phagocytes / Q000187:drug effects / Q000502:physiology*; D010587:Phagocytosis / Q000187:drug effects* / Q000502:physiology; D017476:Receptors, Neuropeptide Y / Q000037:antagonists & inhibitors* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects* / Q000502:physiology; D013154:Spleen / Q000166:cytology / Q000378:metabolism; D013449:Sulfonamides / Q000494:pharmacology
chemical_list: D000067956:Adenylyl Cyclase Inhibitors; D019167:Appetite Stimulants; D004791:Enzyme Inhibitors; D007546:Isoquinolines; D009478:Neuropeptide Y; D017476:Receptors, Neuropeptide Y; D013449:Sulfonamides; C017759:9-(tetrahydro-2-furyl)-adenine; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D000262:Adenylyl Cyclases; D000225:Adenine; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide