Mice were initially anaesthetized with an intraperitoneal injection of pentobarbital sodium [75 mg/kg] and fentanyl [40 mg/kg]. Anaesthesia was maintained with pentobarbital sodium [20 mg/kg] via an intraperitoneal catheter every 30 to 60 minutes. Mice were tracheotomized with a 20-gauge cannula and connected to the ventilator. A catheter was inserted into the carotid artery, which allowed blood pressure monitoring and permanent infusion of 0.9% NaCl (200 mL/h) to prevent hypovolaemia and thrombus formation. Pulsoxymetry was performed with a tail clip (MouseOx, STARR Life-Science, Oakmont, PA, USA). Blood pressure and ECG were recorded permanently (PowerLab, ADInstruments, Spenbach, Germany). Heart rate was calculated from the ECG. Body temperature was measured rectally and kept stable between 36.5uC and 37.5uC by a homeothermic blanket (Harvard Apparatus Holliston, MA, USA).