2.2. Drugs

Psilocin (PSI, THC-Pharm GmbH, Germany) was dissolved in 2 ml of saline (0.9% NaCl) acidified by 10 μl of glacial acetic acid, subsequently adjusted to a volume of 5 ml with saline and administrated in a dose of 4 mg/kg subcutaneously (SC). MDL100907 tartrate 0.5 mg/kg SC (a2A, ABX, GmbH Germany) was dissolved in saline, SB 242084 dihydrochloride 1 mg/kg SC (a2C, Tocris, UK) in cyclodextrin (1 g dextrin + 52 mg citric acid + 10 ml saline, buffered by NaOH to pH 7.4) and WAY100635 maleate 1 mg/kg SC (a1A, Sigma-Aldrich, Germany). Haloperidol 0.1 mg/kg SC (HAL, Sigma-Aldrich, Germany) was dissolved in isotonic glucose solution, and intraperitoneal (IP) clozapine 5 mg/kg, (CLO, Sigma-Aldrich, Germany) was dissolved in saline acidified by a small amount of 0.1 M HCl. Saline served as a vehicle. All drugs were administered in a volume of 2 ml/kg of animal weight. The investigator was not blinded to the treatment.