In vivo experimental stroke and in vitro organ culture induce similar changes in vasoconstrictor receptors and intracellular calcium handling in rat cerebral arteries

TY - JOUR

T1 - In vivo experimental stroke and in vitro organ culture induce similar changes in vasoconstrictor receptors and intracellular calcium handling in rat cerebral arteries

AU - Povlsen, Gro Klitgaard

AU - Waldsee, Roya

AU - Ahnstedt, Hilda

AU - Kristiansen, Kim Anker

AU - Johansen, Flemming Fryd

AU - Edvinsson, Lars

PY - 2012/6

Y1 - 2012/6

N2 - Cerebral arteries subjected to different types of experimental stroke upregulate their expression of certain G-protein-coupled vasoconstrictor receptors, a phenomenon that worsens the ischemic brain damage. Upregulation of contractile endothelin B (ETB) and 5-hydroxytryptamine IB (5-HTIB) receptors has been demonstrated after subarachnoid hemorrhage and global ischemic stroke, but the situation is less clear after focal ischemic stroke. Changes in smooth muscle calcium handling have been implicated in different vascular diseases but have not hitherto been investigated in cerebral arteries after stroke. Here, we evaluate changes of ETBand 5-HT 1Breceptors, intracellular calcium levels, and calcium channel expression in rat middle cerebral artery (MCA) after focal cerebral ischemia and in vitro organ culture, a proposed model of vasoconstrictor receptor changes after stroke. Rats were subjected to 2 h MCA occlusion followed by reperfusion for 1 or 24 h. Alternatively, MCAs from naïve rats were cultured for 1 or 24 h. ETBand 5-HT1Breceptor-mediated contractions were evaluated by wire myography. Receptor and channel expressions were measured by real-time PCR and immunohistochemistry. Intracellular calcium was measured by FURA-2. Expression and contractile functions of ETBand 5-HT 1Breceptors were strongly upregulated and slightly downregulated, respectively, 24 h after experimental stroke or organ culture. ET Breceptor-mediated contraction was mediated by calcium from intracellular and extracellular sources, whereas 5-HT1Breceptor- mediated contraction was solely dependent on extracellular calcium. Organ culture and stroke increased basal intracellular calcium levels in MCA smooth muscle cells and decreased the expression of inositol triphosphate receptor and transient receptor potential canonical calcium channels, but not voltage-operated calcium channels.

AB - Cerebral arteries subjected to different types of experimental stroke upregulate their expression of certain G-protein-coupled vasoconstrictor receptors, a phenomenon that worsens the ischemic brain damage. Upregulation of contractile endothelin B (ETB) and 5-hydroxytryptamine IB (5-HTIB) receptors has been demonstrated after subarachnoid hemorrhage and global ischemic stroke, but the situation is less clear after focal ischemic stroke. Changes in smooth muscle calcium handling have been implicated in different vascular diseases but have not hitherto been investigated in cerebral arteries after stroke. Here, we evaluate changes of ETBand 5-HT 1Breceptors, intracellular calcium levels, and calcium channel expression in rat middle cerebral artery (MCA) after focal cerebral ischemia and in vitro organ culture, a proposed model of vasoconstrictor receptor changes after stroke. Rats were subjected to 2 h MCA occlusion followed by reperfusion for 1 or 24 h. Alternatively, MCAs from naïve rats were cultured for 1 or 24 h. ETBand 5-HT1Breceptor-mediated contractions were evaluated by wire myography. Receptor and channel expressions were measured by real-time PCR and immunohistochemistry. Intracellular calcium was measured by FURA-2. Expression and contractile functions of ETBand 5-HT 1Breceptors were strongly upregulated and slightly downregulated, respectively, 24 h after experimental stroke or organ culture. ET Breceptor-mediated contraction was mediated by calcium from intracellular and extracellular sources, whereas 5-HT1Breceptor- mediated contraction was solely dependent on extracellular calcium. Organ culture and stroke increased basal intracellular calcium levels in MCA smooth muscle cells and decreased the expression of inositol triphosphate receptor and transient receptor potential canonical calcium channels, but not voltage-operated calcium channels.

KW - Animals

KW - Calcium

KW - Cerebral Arteries

KW - Disease Models, Animal

KW - Dose-Response Relationship, Drug

KW - Intracellular Fluid

KW - Male

KW - Muscle, Smooth, Vascular

KW - Organ Culture Techniques

KW - Rats

KW - Rats, Wistar

KW - Receptor, Endothelin B

KW - Receptor, Serotonin, 5-HT1B

KW - Stroke

KW - Vasoconstriction

KW - Viper Venoms

U2 - 10.1007/s00221-012-3108-6

DO - 10.1007/s00221-012-3108-6

M3 - Journal article

C2 - 22585122

SN - 0014-4819

VL - 219

SP - 507

EP - 520

JO - Experimental Brain Research

JF - Experimental Brain Research

IS - 4

ER -