Fig. 4. Effect of lyral on Ca²⁺ levels in spermatogenic cells and spermatozoa. (A) Pseudocolored image and representative trace of Ca²⁺ levels in spermatogenic cells. Different concentrations of lyral were applied for 15 seconds during the times indicated by the bars and cells were continuously washed with buffer between stimulant applications. K8.6, a high potassium solution, was used as a positive control for cell viability. (top) Pseudocolored images of the Ca²⁺ levels. The cells indicated with white arrows display dose-dependent effects of lyral (scale bar, 20 µm). (bottom) Recordings of the change in fluorescence from single spermatogenic cell. (B) Pseudocolored image and representative trace of Ca²⁺ levels in cauda epididymal sperm. The response profile shows the change of F ratio calculated in the entire area of the responding sperm head. Arrows indicate the application of an odorant or K8.6. Lyral (LY) but not bourgeonal (Bour) increased the level of Ca²⁺ in epididymal sperm. Scale bar, 4 µm.