Figure 5.

Slow phase of Ca²⁺ signal depends on release from presynaptic ryanodine-sensitive stores, and the fast phase depends partially on influx via T-type or R-type VGCCs. A, Average presynaptic terminal Ca²⁺ rise during LTD induction protocol (n = 11). Arrows point to fast and slow phases. Selective presynaptic application of CPA (30 μm; n = 15; B) or ryanodine (300 μm; n = 5; C) selectively inhibits the slow phase. D, Bath application of d-APV (50 μm) does not affect either the fast or slow phase (n = 3). E, Bath application of Ni²⁺ (50 μm) prevents the slow phase and partially inhibits the fast phase (n = 4). F, Summary data from all terminal imaging experiments. The asterisk indicates condition that is significantly different from control (post hoc Fisher LSD test; p < 0.05).