Fig. 6. Ca²⁺ dynamics during the rising phase of 5-HT-induced Ca²⁺ transients. The data in A and B were obtained from the first Ca²⁺ transient (initiated at 0) and the fifth transient (initiated at 1278 seconds), respectively, in the same oocyte for Fig. 5A. In C, a rising pattern of the third transient (initiated at 537 seconds) in the oocyte for Fig. 5B was investigated. Sequential fluorescence images were acquired every 0.4 seconds, normalized by dividing them by the resting image just before each Ca²⁺ increase in a pixel-to-pixel manner, and expressed as pseudocolor images. The zero time in each montage was defined as the initiation time of each Ca²⁺ transient, which is independent of the time of 5-HT addition.