GluN2B-dependence of LTD is created in the sagittal slice by a muscarinic acetylcholine receptor antagonist. A) Sagittal slices were again used for extracellular recordings of synaptic activity. After a stable baseline stimulation period (0.03 Hz, >30 minutes), the muscarinic receptor antagonist scopolamine (Scop, 20 μM) was added to the aCSF with or without GluN2B-selective antagonist Ro (5 μM) and stimulation continued at baseline frequency for another 30 minutes. LFS was then begun while drug application continued. Drug washout began at the termination of LFS and the magnitude of LTD was quantified in the final 10 minutes of the hour after LFS. B) In the sagittal slices, application of scopolamine did not change the induction of LTD or the baseline fEPSP. However, when co-applied with GluN2B antagonist Ro there was a significant inhibition of LTD compared to the slices treated with scopolamine alone. Scale bars represent 10 ms and 0.5 mV.