title: Cerebral aneurysm progression suppressed by blockage of endothelin B receptor.
abstract: OBJECTIVE
  Cerebral aneurysm is a major cause of subarachnoid hemorrhage, but the mechanisms of its development remain unclear. Mechanical stretch has been reported to induce vascular smooth-muscle cell apoptosis via endothelin B receptors (ETBRs). The objectives of this study were to clarify the expression and localization of ETBR in cerebral aneurysms and to examine the effect of ETBR blockage on the development of experimental cerebral aneurysms.
  
  
  METHODS
  Seventy-two rats underwent a cerebral aneurysm induction procedure and were divided into four groups according to the duration of postoperative study periods. Expression of ETBR was confirmed by reverse transcription-polymerase chain reaction and immunohistochemical analysis. The authors also studied the effect of K-8794, an oral selective antagonist of ETBR, to see whether it would influence the formation of cerebral aneurysms. Two weeks after the aneurysm induction procedure, ETBR was rarely detected in anterior cerebral artery-olfactory artery bifurcations, but it was weakly expressed in experimental cerebral aneurysms at 1 month after the procedure, and markedly expressed at 3 months. The administration of K-8794 for 1 month after the procedure significantly reduced the number of advanced aneurysms and the number of apoptotic smooth-muscle cells.
  
  
  CONCLUSIONS
  These results suggest that ETBR might play a significant role in the progression of cerebral aneurysms and have the potential to improve prevention and treatment of cerebral aneurysms.
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Nobutake
authors.initials: N
authors.lastname: Sadamasa
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Nozaki
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Takagi
authors.forename: Takuya
authors.initials: T
authors.lastname: Moriwaki
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Kawanabe
authors.forename: Masatsune
authors.initials: M
authors.lastname: Ishikawa
authors.forename: Nobuo
authors.initials: N
authors.lastname: Hashimoto
mesh_terms: D000368:Aged; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D065131:Endothelin B Receptor Antagonists; D004730:Endothelium, Vascular / Q000378:metabolism; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000209:etiology / Q000378:metabolism* / Q000517:prevention & control*; D009131:Muscle, Smooth, Vascular / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D044023:Receptor, Endothelin B / Q000235:genetics / Q000378:metabolism*
chemical_list: D065131:Endothelin B Receptor Antagonists; D012333:RNA, Messenger; D044023:Receptor, Endothelin B