Fig. 1. Spontaneous [Ca²⁺]_i oscillation seen in a c-Kit-immunopositive region of a cell cluster preparation in the presence of cromakalim. (a,b) Fluo-3 Ca²⁺ images acquired from a cell cluster preparation at basal and peak times of an oscillation cycle, respectively. The Ca²⁺ image in b was normalized to a [(a)=F₀, (b)=F_peak/F₀]. This cell cluster preparation was treated with 3 µM cromakalim. (c,d) A transmission image of the same cell cluster and an immunostaining with an anti-c-Kit antibody, ACK2, respectively. This immunostaining was done after the [Ca²⁺]_i measurement. Scale bars: (below b for a and b, and below d for c and d) 50 µm.