2.1 Animals
Adult male Sprague‒Dawley rats (RRID: MGI: 5651135) (250-280 g weight) were procured from the Animal Center of Peking University (Beijing, China). The rats were housed individually in plastic cages with ad libitum access to food and water at an optimum temperature of 25 ± 2°C and 55-65% relative humidity. The position of the bottle was in the middle of the cage cover to eliminate location bias. A 12 h/12 h light/dark cycle (lights on at 9:00 AM) was regulated in the animal house. All rats were allowed to acclimate for 7 d before receiving any experimental manipulation. All the experimental procedures were carried out under the guidelines of the ”Animal Research: Reporting of In Vivo Experiments (ARRIVE)”(Percie du Sert, Hurst et al., 2020) and the recommendations made by the British Journal of Pharmacology (BJP)(Lilley, Stanford et al., 2020). The animal experiment protocol was approved by the Peking University Committee on Animal Care and Use (permission no. LA 2020279).