Figure 5.

Effects of ion channel blockers on intracellular Ca²⁺ and sperm motility. Semen was diluted in FPS containing calcium green1-AM to load the dye as described in Materials and Methods. The dye-loaded sperm was suspended in FPS with or without 5 mM 4-AP or 100 μM verapamil for 5 min, and then distilled water with or without the blockers was added (arrowhead). The changes of fluorescence were monitored by fluorescence spectrophotometer as described in Materials and Methods. Note that intensive increase in intracellular Ca²⁺ occurs within 10 sec after exposure of sperm to hypotonic environment in which sperm motility is initiated. Verapamil and 4-AP block both sperm motility and the increase in intracellular Ca²⁺.