Neurons were incubated in the standard bath solution supplemented with 5μCi of 45Ca. 45Ca accumulation was measured at 1, 3, and 5 minutes after application of 10μM (open symbols) or 100μM glutamate (filled symbols) as indicated. Non-specific 45Ca binding, measured in the presence of 10μM MK801 (an inhibitor of NMDA receptors), 10μM CNQX (an inhibitor of AMPA receptors), and 5μM nifedipine (a blocker of voltage-gated Ca2+ channels) was subtracted from 45Ca accumulation in the absence of inhibitors. Data are mean±SEM, N=3.