@article{KraftSchwarzPochetetal.2010, author = {Kraft, P. and Schwarz, T. and Pochet, L. and Stoll, G. and Kleinschnitz, Christoph}, title = {COU254, a specific 3-carboxamide-coumarin inhibitor of coagulation factor XII, does not protect mice from acute ischemic stroke}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-68103}, year = {2010}, abstract = {Background: Anticoagulation is an important means to prevent from acute ischemic stroke but is associated with a significant risk of severe hemorrhages. Previous studies have shown that blood coagulation factor XII (FXII)- deficient mice are protected from pathological thrombus formation during cerebral ischemia without bearing an increased bleeding tendency. Hence, pharmacological blockade of FXII might be a promising and safe approach to prevent acute ischemic stroke and possibly other thromboembolic disorders but pharmacological inhibitors selective over FXII are still lacking. In the present study we investigated the efficacy of COU254, a novel nonpeptidic 3-carboxamide-coumarin that selectively blocks FXII activity, on stroke development and post stroke functional outcome in mice. Methods: C57Bl/6 mice were treated with COU254 (40 mg/kg i.p.) or vehicle and subjected to 60 min transient middle cerebral artery occlusion (tMCAO) using the intraluminal filament method. After 24 h infarct volumes were determined from 2,3,5-Triphenyltetrazoliumchloride(TTC)-stained brain sections and functional scores were assessed. Hematoxylin and eosin (H\&E) staining was used to estimate the extent of neuronal cell damage. Thrombus formation within the infarcted brain areas was analyzed by immunoblot. Results: Infarct volumes and functional outcomes on day 1 after tMCAO did not significantly differ between COU254 pre-treated mice or untreated controls (p > 0.05). Histology revealed extensive ischemic neuronal damage regularly including the cortex and the basal ganglia in both groups. COU254 treatment did not prevent intracerebral fibrin(ogen) formation. Conclusions: COU254 at the given concentration of 40 mg/kg failed to demonstrate efficacy in acute ischemic stroke in this preliminary study. Further preclinical evaluation of 3-carboxamide-coumarins is needed before the antithrombotic potential of this novel class of FXII inhibitors can be finally judged.}, subject = {Schlaganfall}, language = {en} } @article{EhlingBittnerBobaketal.2010, author = {Ehling, P. and Bittner, S. and Bobak, N. and Schwarz, T. and Wiendl, H. and Budde, T. and Kleinschnitz, Christoph and Meuth, S. G.}, title = {Two pore domain potassium channels in cerebral ischemia: a focus on K2p9.1 (TASK3, KCNK9)}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-68129}, year = {2010}, abstract = {BACKGROUND: Recently, members of the two-pore domain potassium channel family (K2P channels) could be shown to be involved in mechanisms contributing to neuronal damage after cerebral ischemia. K2P3.1-/- animals showed larger infarct volumes and a worse functional outcome following experimentally induced ischemic stroke. Here, we question the role of the closely related K2P channel K2P9.1. METHODS: We combine electrophysiological recordings in brain-slice preparations of wildtype and K2P9.1-/- mice with an in vivo model of cerebral ischemia (transient middle cerebral artery occlusion (tMCAO)) to depict a functional impact of K2P9.1 in stroke formation. RESULTS: Patch-clamp recordings reveal that currents mediated through K2P9.1 can be obtained in slice preparations of the dorsal lateral geniculate nucleus (dLGN) as a model of central nervous relay neurons. Current characteristics are indicative of K2P9.1 as they display an increase upon removal of extracellular divalent cations, an outward rectification and a reversal potential close to the potassium equilibrium potential. Lowering extracellular pH values from 7.35 to 6.0 showed comparable current reductions in neurons from wildtype and K2P9.1-/- mice (68.31 +/- 9.80\% and 69.92 +/- 11.65\%, respectively). These results could be translated in an in vivo model of cerebral ischemia where infarct volumes and functional outcomes showed a none significant tendency towards smaller infarct volumes in K2P9.1-/- animals compared to wildtype mice 24 hours after 60 min of tMCAO induction (60.50 +/- 17.31 mm3 and 47.10 +/- 19.26 mm3, respectively). CONCLUSIONS: Together with findings from earlier studies on K2P2.1-/- and K2P3.1-/- mice, the results of the present study on K2P9.1-/- mice indicate a differential contribution of K2P channel subtypes to the diverse and complex in vivo effects in rodent models of cerebral ischemia.}, subject = {Kaliumkanal}, language = {en} }