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 -