TRPM8, a Versatile Channel in Human Sperm
Figure 5
Lowering temperature from 25 to 13°C increases [Ca2+]i in human sperm.
[Ca2+]i was monitored after loading cells with Fluo3-AM (2 µM) (see methods). Single cell (A and C) and group of cells (B and D) spatio-temporal [Ca2+]i changes induced by cooling (25–13°C) (red to blue bar) in the absence (A and B) or presence (C and D) of 20 µM Cz (gray bar). The panels to the right illustrate representative [Ca2+]i traces of the corresponding field during the temperature ramp in the absence (A and B) or presence (C and D) of 20 µM Cz. The time frame is indicated in each panel. Scales indicate (F/F0) -1 vs time (sec). Note: about 28% of cells responded to menthol. Color coding: black (−) to red (+) indicates low to high [Ca2+]. n≥3.