title: Upregulation of relaxin after experimental subarachnoid hemorrhage in rabbits.
abstract: BACKGROUND
  Although relaxin causes vasodilatation in systemic arteries, little is known about its role in cerebral arteries. We investigated the expression and role of relaxin in basilar arteries after subarachnoid hemorrhage (SAH) in rabbits.
  
  
  METHODS
  Microarray analysis with rabbit basilar artery RNA was performed. Messenger RNA expression of relaxin-1 and relaxin/insulin-like family peptide receptor 1 (RXFP1) was investigated with quantitative RT-PCR. RXFP1 expression in the basilar artery was investigated with immunohistochemistry. Relaxin concentrations in cerebrospinal fluid (CSF) and serum were investigated with an enzyme-linked immunosorbent assay. Using human brain vascular smooth muscle cells (HBVSMC) preincubated with relaxin, myosin light chain phosphorylation (MLC) was investigated with immunoblotting after endothelin-1 stimulation.
  
  
  RESULTS
  After SAH, RXFP1 mRNA and protein were significantly downregulated on day 3, whereas relaxin-1 mRNA was significantly upregulated on day 7. The relaxin concentration in CSF was significantly elevated on days 5 and 7. Pretreatment with relaxin reduced sustained MLC phosphorylation induced by endothelin-1 in HBVSMC.
  
  
  CONCLUSIONS
  Upregulation of relaxin and downregulation of RXFP1 after SAH may participate in development of cerebral vasospasm. Downregulation of RXFP1 may induce a functional decrease in relaxin activity during vasospasm. Understanding the role of relaxin may provide further insight into the mechanisms of cerebral vasospasm.
authors.affiliation: Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Kikkawa
authors.affiliation: Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Matsuo
authors.affiliation: Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan.
authors.forename: Ryota
authors.initials: R
authors.lastname: Kurogi
authors.affiliation: Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Nakamizo
authors.affiliation: Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Mizoguchi
authors.affiliation: Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan.
authors.forename: Tomio
authors.initials: T
authors.lastname: Sasaki
mesh_terms: D000818:Animals; D001488:Basilar Artery / Q000378:metabolism / Q000473:pathology; D002478:Cells, Cultured; D004195:Disease Models, Animal; D019332:Endothelin-1 / Q000494:pharmacology; D006801:Humans; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000473:pathology; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism; D018994:Myosin Light Chains / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D010766:Phosphorylation / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011817:Rabbits; D018000:Receptors, Peptide / Q000235:genetics / Q000378:metabolism; D012065:Relaxin / Q000097:blood / Q000134:cerebrospinal fluid / Q000235:genetics* / Q000378:metabolism; D013345:Subarachnoid Hemorrhage / Q000150:complications / Q000235:genetics* / Q000473:pathology; D013997:Time Factors; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics*; D020301:Vasospasm, Intracranial / Q000209:etiology / Q000473:pathology
chemical_list: D019332:Endothelin-1; D018994:Myosin Light Chains; D012333:RNA, Messenger; D018000:Receptors, Peptide; D012065:Relaxin