Figure 9.

During suprathreshold depolarizations, D1/D5R activation transiently potentiates a secondary Ca²⁺ hump potential that led to spike firing. A, Representative voltage traces showing a single suprathreshold evoked Ca²⁺ spike (arrow). After D1/D5R activation, a Ca²⁺ hump potential emerges that trails the first Ca²⁺ spike. This Ca²⁺ hump potential eventually leads to spiking after 9′ post-D1/D5R activation (open arrow). Eventually, this potentiation subsides and completely disappears before the first Ca²⁺ spike is completely suppressed. B, Graphic representation of the peak amplitude of the first Ca²⁺ spike (filled circle) and the potentiated second Ca²⁺ spike (open circle) after brief D1/D5R activation by DHX for 5 min.