Ly341495

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.

Glutamate receptor blockade was achieved using D-AP5 (50–100 µM; Abcam, UK), NBQX (10 µM; Abcam, UK), R,S-MCPG (500 µM; Abcam, UK) and LY341495 (100 µM; Abcam, UK). L-VGCCs were blocked with nitrendipine (20 µM; Abcam, UK). NO synthase was inhibited by pre-incubation of slices with L-NAME (100 µM; Sigma, UK), which started at least 20 min prior to experimentation. Extracellular NO was scavenged by bath application of cPTIO (50–100 µM; Sigma, UK). Intracellular NO was scavenged by bolus loading cells with 5 mM cPTIO. Endocannabinoid signalling (CB1 receptor) was inhibited by bath application of the AM-251 (2 µM; Tocris, UK).