Figure 3. Hyperpolarization-evoked [Ca²⁺]_i decreases during exposure to ADP.

Megakaryocytes were held at –45 mV and stepped to different hyperpolarized potentials for 10 s duration during the plateau phase of the ADP-evoked [Ca²⁺]_i increase. A, average peak change in [Ca²⁺]_i against amplitude of the hyperpolarizing voltage step. The values are means ±s.e.m. from 13 cells. Hyperpolarizations to potentials of –50 mV to –100 mV were applied in 5 mV increments (see inset) with an interpulse interval of either 10 or 20 s. B, [Ca²⁺]_i response to a 10 s duration voltage step to –100 mV, illustrating the typical larger magnitude of the depolarization-evoked Ca²⁺ increase upon repolarization to –45 mV compared with the initial hyperpolarization-induced Ca²⁺ decrease.