title: EM66-containing neurones in the hypothalamic parvicellular paraventricular nucleus of the rat: no plasticity related to acute immune stress.
abstract: OBJECTIVE
  Neuropeptides, as the main neuroendocrine system effectors, regulate notably the response to different stressors via a secretory plasticity within their respective hypothalamic neuronal populations. The aim of the present study was to explore by immunocytochemistry the occurrence and the potential expression plasticity of the novel neuropeptide EM66 in the CRH neurones of stressed rats.
  
  
  RESULTS
  The secretogranin II (SgII)-derived peptide EM66 is strongly expressed within hypothalamic neuroendocrine areas such as the parvocellular aspect of the paraventricular nucleus (pPVN) as well as the median eminence, suggesting a probable hypophysiotropic effect of this peptide. As a first approach to investigate such a role, we evaluated by immunohistochemistry EM66 expression within the pPVN following acute immune stress induced by lipopolysaccharide (LPS) or interleukin-1β (IL-1β) injection in rat. This study showed that EM66 is present in the pPVN but the number of EM66 immunolabeled cells did not fluctuate in this structure following LPS peripheral injection. In line with this observation, an intracerebroventricular injection of IL-1β did not provoke any significant variation of the number of intraparaventricular EM66 neurones.
  
  
  CONCLUSIONS
  The present data revealed for the first time that EM66 expression would be insensitive to the central and peripheral cytokines within the neurosecretory hypothalamic pPVN. This result indicates that EM66 does not participate to the phenotypic plasticity of hypothalamic parvicellular neurones in response to acute inflammatory stress.
authors.affiliation: Laboratorie de Neuroendocrinologie et Nutritional Environnement Nutritionnel et Climatique, Faculté des Sciences Dhar Mehrez, Université Sidi Mohammed Ben Abdellah, Fès, Morocco.
authors.forename: Fatima-Zohra
authors.initials: FZ
authors.lastname: El Yamani
authors.forename: Laurent
authors.initials: L
authors.lastname: Yon
authors.forename: Marlène
authors.initials: M
authors.lastname: Guérin
authors.forename: Seloua
authors.initials: S
authors.lastname: El Ouezzani
authors.forename: Abdelilah
authors.initials: A
authors.lastname: Alaoui
authors.forename: Nicolas
authors.initials: N
authors.lastname: Chartrel
authors.forename: Youssef
authors.initials: Y
authors.lastname: Anouar
authors.forename: Rabia
authors.initials: R
authors.lastname: Magoul
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D007150:Immunohistochemistry; D007274:Injections, Intraperitoneal; D007276:Injections, Intraventricular; D053583:Interleukin-1beta; D008070:Lipopolysaccharides; D008297:Male; D009473:Neuronal Plasticity; D009479:Neuropeptides / Q000096:biosynthesis*; D010286:Paraventricular Hypothalamic Nucleus / Q000276:immunology / Q000378:metabolism*; D010446:Peptide Fragments / Q000276:immunology / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D053381:Secretogranin II / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D013312:Stress, Physiological / Q000276:immunology
chemical_list: C557436:EM66 peptide; D053583:Interleukin-1beta; D008070:Lipopolysaccharides; D009479:Neuropeptides; D010446:Peptide Fragments; D053381:Secretogranin II