Way161503

Lorcaserin (LGM Pharma, Erlanger KY USA), WAY161,503 (Tocris Bioscience, Abingdon UK) and clozapine-n-oxide (CNO; Tocris Bioscience) were prepared in double distilled H₂O, diluted in sterile phosphate-buffered saline (PBS) and administered in vivo i.p. in a volume of 10 ml/kg. 5-HT (Sigma-Aldrich), lorcaserin, WAY161,503 and CNO were dissolved in artificial cerebrospinal fluid (aCSF) for electrophysiology experiments.

Cocaine hydrochloride (Sigma-Aldrich, St. Louis, USA) were dissolved in sterile 0.9% NaCl and administered iv in a volume of 0.1 ml/infusion or ip in a volume of 1 ml/kg directly before the sessions. Mirtazapine (MIR, Kemprotec, UK), RO 60-0175 (RO, Tocris, Germany), and WAY 161503 (WAY, Tocris, Germany) were dissolved in sterile 0.9% NaCl, and given ip at 15 min (WAY), 20 min (RO) and 30 min (MIR) before test sessions in a volume of 1 ml/kg.

A 5-HT_2C receptor agonist (WAY161503), a 5-HT_2C receptor antagonist (SB242084), and a CRF1 receptor antagonist (NBI27914) were purchased from Tocris Bioscience. Several hours before the start of the electrophysiological recordings, a microdialysis probe (CMA11/Microdialysis; 250 µm membrane diameter; 1 mm membrane length) was lowered vertically into the BLA, ipsilateral to the recording electrode, using the following coordinates: 2.5 mm caudal to bregma, 4.8 mm lateral to midline, 9.0 mm depth. The distance between the microdialysis probe and recording electrode was ~0.5 mm. Before each drug application, artificial cerebrospinal fluid (ACSF) was pumped through the microdialysis fiber for about 1 h at a rate of 5 µL/min to establish equilibrium in the tissue. The microdialysis probe was connected to an infusion pump (Harvard) using PE-50 tubing. The ACSF contained (in mM) 125.0 NaCl, 2.6 KCl, 2.5 NaH2PO4, 1.3 CaCl2, 0.9 MgCl2, 21.0 NaHCO3, and 3.5 glucose oxygenated and equilibrated to pH ± 7.4. Drugs were dissolved in ACSF on the day of the experiment at a concentration of 100 times that was predicted to be needed based on data from our previous studies [36 (link),48 (link),61 (link),91 (link),92 ] and data in the literature [93 (link),94 (link),95 (link)]. Drugs were administered into the BLA at a rate of 5 µL/min.