A DIC snap was first taken for morphological purposes. The exposure time for the fluorescence signal was first set automatically by the software and adjusted manually so that the signals were within the full dynamic range. Either the glow scale look-up table or the histogram was used to monitor the saturation level. Once the parameters were set, they were fixed

click here and used throughout the experiment. For accurate quantification all images were collected in 12 bit gray scale and saved as raw data. Dual channels were used to collect signals from receptor staining (red) and the presynaptic syn-YFP (green). Neurons were transfected with GluA1-GFP at DIV 11 for 3 days. Following a transfer of neurons to a live-imaging chamber maintained at 37°C, dendrites were cleaved manually with a glass micropipette assisted by a micromanipulator, and images

were collected with a 40× (N.A. 1.4) oil objective immediately AZD9291 after cleavage and 60 min later. For MG132 blockade, drugs were applied 15 min prior to dendritic cleavage and during imaging. The mean intensity of the isolated and soma-attached dendrites was measured using NIH ImageJ software. Neurons were transfected at DIV 11 and patch clamped 2–3 days after transfection; LiGluR agonist MAG was diluted to 10 μM in a bath solution containing 150 mM NMDG-HCl, 3 mM KCl, 0.5 mM CaCl2, 5 mM MgCl2, 10 mM HEPES, and 10 mM glucose (pH 7.4). Neurons were incubated at 37°C in the dark for 15 min, then rinsed with extracellular recording solution containing 140 mM NaCl, 3 mM KCl, 1.5 mM MgCl2, 2.5 mM CaCl2, 11 mM glucose, and 10 mM HEPES (pH 7.4). Patch-clamp recordings were performed using an Axopatch 200B amplifier in the whole-cell current clamp mode. Pipettes had resistances of 3–5 MΩ and were filled with a solution containing 110 mM K-methanesulfonate, 20 mM KCl, 10 mM

HEPES, 4 mM Mg-ATP, 0.3 mM Na-GTP, 0.5 mM EGTA, and 10 mM Na-phosphocreatine (pH 7.4). Cells were used for UV stimulation when the resting membrane potential was between −50 and −65 mV. Illumination was applied using an X-Cite Series 120 over light source through the rear port of an inverted microscope (Nikon; Eclipse TE300) using a 40× objective. The physiology rig was fitted with UV (380 nm) and blue (480 nm) filters that were switched manually to illuminate neurons for approximately 1 s with UV or blue light, respectively. Electrophysiological data were recorded and analyzed with pClamp 10 software. To measure the synaptic content of AMPAR puncta, a double-colored image (red from stained glutamate receptors or other proteins and green signals from syn-YFP) was separated into two channels with NIH ImageJ software. The red channels were thresholded to select AMPAR puncta for quantitative measurement; then the two windows were synchronized.