Mk 801 maleate

Pharmacological agents were purchased from: Sigma-Aldrich: Fluoroacetate, thapsigargin, BAPTA, bicuculline methbromide, Tricine, Zinc chloride, d-serine, and GDPβS; Tocris Bioscience: nimodipine, (+)-MK-801 maleate, d-AP5, NBQX, TTX citrate, PPDA, Ro 25-6981 maleate, MCPG, MPEP, LY341495, AM251, 2-AG, and FK506; and Abcam: UBP-141. Salts used for internal and external solutions were purchased from Sigma-Aldrich. Compounds were dissolved in H₂O or Ringer solution with the exception of thapsigargin, nimodipine, PPDA, FK506, THL, AM251, and 2-AG, which were dissolved in DMSO. Vehicle (DMSO) at the concentrations used did not affect baseline EPSP amplitudes and had no other detectable effects on the neurons. When investigating the effect of pharmacological agents on plasticity, all drugs were included in the superfusion fluid or patch pipette from the start of the experiment until completion (from 0 to 50 min in a standard plasticity experiment), except for Fluoroacetate, which was applied from 60 min before the start of recording. When determining the effect of a pharmacological agent on baseline condition, a stable baseline of at least 10 min was first recorded and then the drug was bath applied by switching to a different perfusion line.

1-Aminocyclopropanecarboxylic acid (ACPC) kindly donated by Dr. M-L Maccecchini, phencyclidine hydrochloride (Sigma-Aldrich, USA), ketamine (aqueous solution (115.34 mg/ml; Biowet Pulawy, Poland)), and MK-801 maleate (Abcam Biochemicals, Cambridge, UK) were dissolved in distilled water. Clozapine (Abcam Biochemicals, Cambridge, UK) was dissolved in 0.1 N HCl supplemented with distilled water to the appropriate volume (final pH = 5.0–6.0). All compounds were administrated in a volume of 1 ml/kg, except ACPC at 400 mg/kg which was administered in a volume of 2 ml/kg due to solubility limitations.

The chemicals used to make the ACSF were purchased from Panreac or Merck. Mg‐ATP, Na‐GTP, and phosphocreatine disodium salt hydrate for the internal solution were obtained from Sigma‐Aldrich. Stock solutions of 5‐CT (5‐carboxamidotryptamine maleate salt; Sigma‐Aldrich, Madrid, Spain), baclofen [(R)‐4‐Amino‐3‐(4‐chlorophenyl)butanoic acid; Abcam, Cambridge, UK], CGP55845 (CGP55845 hydrochloride; Abcam, Cambridge, UK), GABA (4‐aminobutanoic acid; Abcam), tertiapin‐Q (Tocris, Bristol, UK), and WAY100635 (N‐[2‐[4‐(2‐methoxyphenyl)‐1‐piperazinyl]ethyl]‐N‐2‐pyridinylcyclohexanecarboxamide maleate salt; Sigma‐Aldrich) were prepared in distilled water. DNQX [6,7‐dinitroquinoxaline‐2,3‐dione; Abcam] and MK‐801 [(+)‐MK‐801 maleate; Abcam] were prepared in DMSO (dimethyl sulfoxide). Drug stocks were diluted in artificial cerebrospinal fluid (ACSF) immediately before application. The highest experimental concentration of DMSO was 0.01%. Isoflurane was purchased from Abbott.