Figure 3.

Calcium entry occurs through NMDAR channels. In this experiment, the cells were pretreated with 5 μM MK-801 for 5 min, and the NMDAR antagonist remained in the bath throughout the procedure. At t = 350 sec, 35 nM α₂M* was added to the bath, resulting in a small but insignificant increase in [Ca²⁺]_i in this field of cells. At t = 700 sec, 100 μM NMDA was added, and no change in [Ca²⁺]_i was observed. Glutamate (10 μM), however, was capable of eliciting a calcium response at t = 900 sec. This is a representative trace of n = 4 experiments and is the mean of n = 15 neurons in a field.