title: Cytokines and growth factors modify the upregulation of contractile endothelin ET(A)  and ET(B)  receptors in rat cerebral arteries after organ culture.
abstract: OBJECTIVE
  Experimental cerebral ischaemia and organ culture of cerebral arteries induce an increased endothelin ET(B)  receptor-mediated contraction. The aim of this study was to examine whether cytokines and growth factors, known to be activated in ischaemia, can influence the expression and function of endothelin receptors after organ culture.
  
  
  METHODS
  Rat middle cerebral arteries were cultured for 24 h at 37 °C in humidified 5% CO(2)  and air in culture medium alone, or with tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β), platelet-derived growth factor (PDGF), epidermal growth factor (EGF) or basic fibroblast growth factor (bFGF). Concentration-response curves were obtained for sarafotoxin 6c (ET(B)  receptor agonist) and endothelin-1 (here ET(A)  receptor agonist, because of ET(B)  receptor desensitization). The receptor mRNA expression was examined by real-time PCR and the protein expression by immunohistochemistry and Western blot.
  
  
  RESULTS
  Tumour necrosis factor-α (100 ng mL(-1) ) and EGF (20 ng mL(-1) ) potentiated the ET(B)  receptor-mediated contraction (increase in pEC(50)  without change in E(max) ). bFGF (10 ng mL(-1) ) and IL-1β (10 ng mL(-1) ) induced an enhanced ET(A)  receptor-mediated contraction. bFGF (10 ng mL(-1) ) significantly increased the ET(B)  mRNA level, and EGF (20 ng mL(-1) ) increased the ET(A)  receptor protein. Increased ET(B)  receptor mRNA and protein level also were observed after treatment with IL-1β (10 ng mL(-1) ).
  
  
  CONCLUSIONS
  This study shows that TNF-α, IL-1β, EGF and bFGF can modify the expression and function of endothelin receptors during organ culture. Because there is similar receptor upregulation in experimental stroke, the effect of cytokines and growth factors on endothelin receptor upregulation is an interesting aspect to study in vivo.
authors.affiliation: Division of Experimental Vascular Research, Department of Clinical Sciences, Lund University, Lund, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Ahnstedt
authors.forename: E
authors.initials: E
authors.lastname: Stenman
authors.forename: L
authors.initials: L
authors.lastname: Cao
authors.forename: M
authors.initials: M
authors.lastname: Henriksson
authors.forename: L
authors.initials: L
authors.lastname: Edvinsson
mesh_terms: D000818:Animals; D002536:Cerebral Arteries / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004815:Epidermal Growth Factor / Q000494:pharmacology; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D053583:Interleukin-1beta / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009924:Organ Culture Techniques; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D044022:Receptor, Endothelin A / Q000378:metabolism*; D044023:Receptor, Endothelin B / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects*
chemical_list: D053583:Interleukin-1beta; D010982:Platelet-Derived Growth Factor; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D014409:Tumor Necrosis Factor-alpha; D016222:Fibroblast Growth Factor 2; D004815:Epidermal Growth Factor