title: Protein kinase C inhibition prevents upregulation of vascular ET(B) and 5-HT(1B) receptors and reverses cerebral blood flow reduction after subarachnoid haemorrhage in rats.
abstract: The pathogenesis of cerebral ischaemia after subarachnoid haemorrhage (SAH) still remains elusive. The purpose of the present study was to examine whether specific protein kinas C (PKC) inhibition in rats could alter the transcriptional SAH induced Endothelin (ET) type B and 5-hydroxytryptamine type 1B (5-HT(1B)) receptor upregulation and prevent the associated cerebral blood flow (CBF) reduction. The PKC inhibitor RO-31-7549 or vehicle was injected intracisternally after the induced SAH in rats (n=3 to 10 in each groups for each method). The involvement of the PKC isoforms was investigated with Western blot; only PKCdelta and PKCalpha subtypes were increased after SAH RO-31-7549 treatment abolished this. At 2 days after the SAH basilar and middle cerebral arteries were harvested and the contractile response to endothelin-1 (ET-1; ET(A) and ET(B) receptor agonist) and 5-carboxamidotryptamine (5-CT; 5-HT(1) receptor agonist) were investigated with a myograph. The contractile responses to ET-1 and 5-CT were increased (P<0.05) after SAH compared with sham operated rats. In parallel, the ET(B) and 5-HT(1B) receptor mRNA and protein expression were significantly elevated after SAH, as analysed by quantitative real-time polymerase chain reaction and immunohistochemistry, respectively. Administration of RO-31-7549 prevented the upregulated contraction elicited by application of ET-1 and 5-CT in cerebral arteries and kept the ET(B) and 5-HT(1B) receptor mRNA and protein levels at pre-SAH levels. Regional and global CBF evaluated by an autoradiographic technique were reduced by 60%+/-4% after SAH (P<0.05) and prevented by treatment with RO-31-7549. Our study suggests that PKC plays an important role in the pathogenesis of cerebral ischaemia after SAH.
authors.affiliation: Department of Clinical Sciences, Division of Experimental Vascular Research, Lund University Hospital, Lund, Sweden. Saema.Beg@med.lu.se
authors.forename: Saema S
authors.initials: SS
authors.lastname: Beg
authors.forename: Jacob A
authors.initials: JA
authors.lastname: Hansen-Schwartz
authors.forename: Petter J
authors.initials: PJ
authors.lastname: Vikman
authors.forename: Cang-Bao
authors.initials: CB
authors.lastname: Xu
authors.forename: Lars I
authors.initials: LI
authors.lastname: Edvinsson
mesh_terms: D000465:Algorithms; D000818:Animals; D001345:Autoradiography; D001488:Basilar Artery / Q000187:drug effects; D015153:Blotting, Western; D002196:Capillaries / Q000473:pathology; D002536:Cerebral Arteries / Q000473:pathology; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D019332:Endothelin-1 / Q000096:biosynthesis* / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D007150:Immunohistochemistry; D007211:Indoles / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D011506:Proteins / Q000032:analysis / Q000378:metabolism; D051381:Rats; D044302:Receptor, Serotonin, 5-HT1B / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012701:Serotonin / Q000031:analogs & derivatives / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D013345:Subarachnoid Hemorrhage / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology*; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D019332:Endothelin-1; D004791:Enzyme Inhibitors; D007211:Indoles; D008301:Maleimides; D011506:Proteins; D044302:Receptor, Serotonin, 5-HT1B; D017366:Serotonin Receptor Agonists; D012701:Serotonin; C047087:5-carboxamidotryptamine; D011493:Protein Kinase C; C064755:Ro 31-7549