Direct comparison of time courses for membrane current and Ca 2+ signal in the same location of the cilium. (A) Photomicrograph of a single ORC. The ROI selected for both fluorescence measurements and UV irradiation is indicated by a white square. In this experiment, the ROIs used for imaging and UV stimulation were the same. (B) Analysis ROIs on the single cilium (red circles, 0.23 µm in diameter). The total area that appeared in B corresponds to the area marked by a white square in A. Ten small analysis ROIs were used for measuring fluorescence and data obtained from them were averaged. (C) The current response to a UV stimulus (1.52 s) using bleach mode (white square in A as a stimulus ROI). Scaling Y, 0.045 µm. (D) Fluorescence intensity. Plots are means of fluorescence intensities obtained from analysis ROIs in the UV irradiation area (n = 10), as shown in B. Error bars show the SD from those data. Image data and the fluorescence signal during UV irradiation could not be obtained in bleach mode. Scan speed, 0.20 s/scan. Line sum, 2. (E) Superimposition of the current response and fluorescence intensity. The data were adjusted by both the peak value and basal level. (F) The current response to double-pulse stimulation. (G) Fluorescence intensity changes during the double-pulse stimulus. The image scan speed was 0.20 s/scan. (H) Superimposition of the current response and fluorescence intensity for the double-pulse stimulus.