title: Orexins/hypocretins stimulate accumulation of inositol phosphate in primary cultures of rat cortical neurons.
abstract: BACKGROUND
  Orexins A and B (also named hypocretins 1 and 2) are hypothalamic peptides with pleiotropic activity. They signal through two G protein-coupled receptors: OX1R and OX2R. We have previously demonstrated that both types of orexin receptors are expressed in cultured rat cortical neurons, and stimulation of the predominant OX2R inhibits cyclic AMP synthesis. In the present work, we examined effects of orexins on inositol phosphate (IP) accumulation in rat cortical neurons.
  
  
  METHODS
  Experiments were performed on primary neuronal cell cultures prepared from Wistar rat embryos on day 17 of gestation. Following 1 h incubation with orexins, IP levels were measured using the ELISA IP-One assay kit.
  
  
  RESULTS
  Orexins A and B increased, in a concentration-dependent manner, IP accumulation in primary neuronal cell cultures from rat cerebral cortex. Both peptides acted with a similar potency. The calculated EC50 values were 6.0 nM and 10.4 nM for orexin A and orexin B, respectively.
  
  
  CONCLUSIONS
  The results indicate that in cultured rat cortical neurons orexin receptors are also coupled to inositol phosphates signaling pathway.
authors.affiliation: Institute for Medical Biology, Polish Academy of Sciences, Lodowa 106, PL 93-232 Łódź, Poland. jolanta.zawilska@umed.lodz.pl
authors.forename: Jolanta B
authors.initials: JB
authors.lastname: Zawilska
authors.forename: Anna
authors.initials: A
authors.lastname: Urbańska
authors.forename: Paulina
authors.initials: P
authors.lastname: Sokołowska
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism*; D000242:Cyclic AMP / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D007295:Inositol Phosphates / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins / Q000008:administration & dosage / Q000378:metabolism* / Q000494:pharmacology; D009474:Neurons / Q000378:metabolism; D009479:Neuropeptides / Q000008:administration & dosage / Q000378:metabolism* / Q000494:pharmacology; D064446:Orexin Receptors / Q000378:metabolism*; D000068797:Orexins; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction
chemical_list: D007295:Inositol Phosphates; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D064446:Orexin Receptors; D000068797:Orexins; D000242:Cyclic AMP