Fig. 1.
Study design. (A) A cohort of 12- to 14-week-old mice were randomly allocated to 10 groups (n = 14/group) and were pretreated intraperitoneally with antagonists (atipamezole/yohimbine/prazosin). Thirty minutes later, mice were trained in the trace fear conditioning paradigm. After the training session, lipopolysaccharide or vehicle was administered intraperitoneally. Dexmedetomidine was administered every 2 h for a total of three doses. Three days after lipopolysaccharide, testing was performed in the trace fear conditioning. (B) Another cohort of 12- to 14-week-old mice were randomly allocated to 6 groups (n = 8/group) and were pretreated intraperitoneally with antagonists (atipamezole/yohimbine/prazosin), and 30 min later lipopolysaccharide was administered. Dexmedetomidine was administered every 2 h for a total of three times. Blood and tissue were collected 6 h later. (C) RAW 264.7 and BV-2 cells were allocated to 4 groups (n = 6/group) and were pretreated with yohimbine, and 30 min later were treated with dexmedetomidine and lipopolysaccharide. The supernatant and cell pellet were collected 24 h later. (D) A cohort of 12-month-old mice were randomly allocated to 4 groups (n = 12/group) for behavioral assessment and underwent the same procedures as for younger mice (those shown in A). (E) Another cohort of 12-month-old mice were randomly allocated to 4 groups (n = 8/group) for inflammation assessment and underwent the same procedures as for younger mice (those shown in B).