title: CaMKII inhibition with KN93 attenuates endothelin and serotonin receptor-mediated vasoconstriction and prevents subarachnoid hemorrhage-induced deficits in sensorimotor function.
abstract: BACKGROUND
  It has been suggested that transcriptional upregulation of cerebral artery contractile endothelin (ETB) and 5-hydroxytryptamine (5-HT1B) receptors play an important role in the development of late cerebral ischemia and increased vasoconstriction after subarachnoid hemorrhage (SAH). We tested the hypothesis that inhibition of calcium calmodulin-dependent protein kinase II (CaMKII) may reduce cerebral vasoconstriction mediated by endothelin and serotonin receptors and improve neurological outcome after experimental SAH.
  
  
  METHODS
  SAH was induced in adult rats by injection of 250 μL autologous blood into the basal cisterns. The CaMKII activity in cerebral vessels was studied by Western blot and immunohistochemistry. The vasomotor responses of middle cerebral and basilar arteries were measured in a sensitive myograph system. The functional outcome was examined by the rotating pole test 2 and 3 days after SAH.
  
  
  RESULTS
  SAH induced a rapid early increase in phosphorylated CaMKII protein at 1 h that was attenuated by cisternal administration of the CaMKII inhibitor KN93 (0.501 μg/kg) 45 min prior and immediately after SAH as evaluated by Western blot. Application of KN93 at 1 h and every 12 h post-SAH significantly reduced vascular CaMKII immunoreactivity at 72 h. In addition, contractile responses of cerebral arteries to endothelin-1 (ET-1) and 5-hydroxycarboxamide (5-CT) were increased at this time-point. KN93 treatment significantly attenuated the contraction induced by ET-1 and 5-CT. Importantly, treatment with the CaMKII inhibitor prevented SAH-induced deficits in neurological function, as evaluated by the rotating pole test, and similar sensorimotor scores were seen in sham-operated animals.
  
  
  CONCLUSIONS
  The present study has shown that SAH is associated with increased contractile responses to ET-1 and 5-CT in cerebral arteries and enhanced early activation of CaMKII. Treatment with the CaMKII inhibitor KN93 attenuated the contractile responses and prevented impaired sensorimotor function after SAH.
authors.affiliation: Division of Experimental Vascular Research, Department of Clinical Sciences, Lund University and Lund University Hospital, Lund, SE-221 84, Sweden. lars.edvinsson@med.lu.se.
authors.forename: Lars
authors.initials: L
authors.lastname: Edvinsson
authors.forename: Gro Klitgaard
authors.initials: GK
authors.lastname: Povlsen
authors.forename: Hilda
authors.initials: H
authors.lastname: Ahnstedt
authors.forename: Roya
authors.initials: R
authors.lastname: Waldsee
mesh_terms: D000818:Animals; D015153:Blotting, Western; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000037:antagonists & inhibitors*; D002536:Cerebral Arteries / Q000187:drug effects / Q000378:metabolism; D002560:Cerebrovascular Circulation / Q000187:drug effects; D004195:Disease Models, Animal; D016232:Endothelins / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007150:Immunohistochemistry; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000378:metabolism*; D013345:Subarachnoid Hemorrhage / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology; D014661:Vasoconstriction / Q000187:drug effects*
chemical_list: D016232:Endothelins; D004791:Enzyme Inhibitors; D011985:Receptors, Serotonin; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2