title: Modification of endothelial nitric oxide synthase through AMPK after experimental subarachnoid hemorrhage.
abstract: Severe subarachnoid hemorrhage (SAH) induces dysfunction of endothelial nitric oxide synthase (eNOS), resulting in severe vasospasm. Clinically, however, some portions of cerebral arteries may show only mild vasospasm. Although severe vasospastic arteries after SAH have been intensively studied, activity of eNOS associated with the mild form of the disease has received less attention. The purpose of the present study was to clarify molecular mechanisms underlying the regulation of eNOS activity in mild vasospastic arteries after SAH. In a rat single-hemorrhage model, basilar arteries were obtained up to 7 days after SAH. Western blot analysis was used to study the temporal profiles of eNOS, phosphorylated (p)-eNOS at Ser(1177) or Thr(495), inducible NOS (iNOS), AMP-activated protein kinase alpha (AMPK alpha, p-AMPK alpha at Thr(172)Akt, p-Akt at Ser(473), cyclic AMP-dependent protein kinase (PKA), and p-PKA at Thr(197) in basilar arteries. Immunohistochemical studies were performed to examine the spatial expression patterns of p-eNOS at Ser(1177) and p-AMPK alpha at Thr(172). Western blot analysis showed eNOS to be significantly phosphorylated at Ser(1177) from 1 to 2 days after SAH, accompanied by upregulation of iNOS and AMPK, while activation states of Akt and PKA did not show significant change. Immunohistochemistry revealed phosphorylation of eNOS and AMPK alpha in endothelial cells of the basilar artery. SAH might thus induce temporary activation of AMPK alpha, which phosphorylates eNOS at Ser(1177) in endothelial cells of mild vasospastic basilar arteries. This signal transduction may play an important role in controlling cerebral blood flow after SAH.
authors.affiliation: Department of Neurological Surgery, Aichi Medical University, Karimata Yazako, Nagakute, Aichi-gun, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Osuka
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Nobuteru
authors.initials: N
authors.lastname: Usuda
authors.forename: Kimie
authors.initials: K
authors.lastname: Atsuzawa
authors.forename: Jun
authors.initials: J
authors.lastname: Yoshida
authors.forename: Masakazu
authors.initials: M
authors.lastname: Takayasu
mesh_terms: D000263:Adenylate Kinase / Q000378:metabolism*; D000704:Analysis of Variance; D000818:Animals; D001488:Basilar Artery / Q000378:metabolism*; D015153:Blotting, Western; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D042783:Endothelial Cells / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D010766:Phosphorylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D013345:Subarachnoid Hemorrhage / Q000378:metabolism*; D013997:Time Factors
chemical_list: D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D017868:Cyclic AMP-Dependent Protein Kinases; D000263:Adenylate Kinase