Figure 2.

Time course of ligand-induced internalization of AMPARs. (A) Cultured neurons were surface labeled with anti-GluR1 antibody, treated with 100 μM AMPA for 0, 1, 5, and 15 min, then immediately chilled on ice, and analyzed for AMPAR internalization by using the acid-strip procedure. Minimal AMPAR internalization is detected until 5 min of AMPA exposure. (B) Internalization of AMPARs can be initiated within 1 min after ligand-induced activation. Cells were incubated in the presence of 100 μM AMPA for 1 min or 5 min and then analyzed by using the acid-strip procedure either immediately (first and third panels) or after agonist washout and chase incubation in the presence of CNQX and d-APV for a total of 15 min (second and fourth panels).