P7791

Noradrenaline-bitartrate(10 nM - 100 μM; I9278, Sigma), the α₁-AR antagonist prazosine (5 µM; P7791, Sigma), the α₂-AR antagonist yohimbine (5 µM; Y3125, Sigma), the α_2A-AR antagonist BRL 44408 (10 μM, C5776, Sigma), the α_2B-AR antagonist ARC 239, the α_1A-AR antagonist WB 4101, the α_1C, D-AR antagonist CEC (1 nM – 1 µM, Q102, Sigma) and the α_1A-AR agonist A61603 (100 nM; A5861, Sigma) were added to the normal aCSF.
To reduce glutamatergic and GABAergic synaptic input to the recorded neurons, 10 µM CNQX (6-cyano-7-nitroquinoxaline-2,3-dione, C127, Sigma-Aldrich), 50 µM DL-AP5 (DL-2-amino-5-phosphonopentanoic acid, BN0086, Biotrend), and 100 µM PTX (picrotoxin, P1675, Sigma Aldrich) was added to the extracellular saline.

Male Sprague Dawley rats (N = 48; initial weight 200-250g) were purchased from Charles River Laboratories (Montreal, QC, Canada). Rats were housed in the York University Vivarium in a 12-hour light-dark cycle. After 7 days acclimation, animals were assigned randomly to receive corticosterone or wax (control) pellets. Furthermore, animals were given either regular water or water containing prazosin hydrochloride (50 mg/L; P7791, Sigma Aldrich Canada) ad libitum. The four experimental groups were as follows: control-water, control-prazosin, CORT-water or CORT-prazosin. All animals were fed a standard rodent chow diet (14% protein, 54% carbohydrate, 32% fat; 3.0 calories/g) ad libitum. CORT (100mg) or wax pellets were made and on Day 0, four pellets were implanted subcutaneously in the mid-scapular region of each rat, under isoflurane anesthesia, as described previously [27 (link)]. Post pellet implantation, animals were provided with a subcutaneous injection of buprenorphine (0.02mg/kg) for analgesia. Subsequently, rodents recovered in individual cages and were given ampicillin (20 mg/kg) in their drinking water. On day 2, rats were continued with regular water or commenced with prazosin-treated water for 7 or 14 days. These groups will be referred to as 1W and 2W control or CORT- water or -prazosin.

Adrenaline (Tonogen, Richter Gedeon, Hungary), 2 mg/kg, was injected intraperitoneally 5 minutes before CTX injection. Adrenaline‐receptor antagonist prazosin (5 mg/kg, P7791, Sigma), yohimbine (1 mg/kg, Y3125, Sigma) and propranolol (3 mg/kg, P0884, Sigma) were dissolved in sterile saline and injected intraperitoneally 15 minutes before TBI.