FIGURE 6.

Pertussis toxin blocks acceleration by Cl-dAdo. Wild-type sperm were treated for 30 min in Medium HS alone (none), or with Ptx (4 μg/ml), heat-inactivated (iPtx; 4 μg/ml), or Ptx B-oligomer (B-oligo; 4 μg/ml). Populations of loosely-tethered sperm from each treatment group were bathed for 2–5 min with Medium HS alone, or with HS fortified with Cl-dAdo (25 μm), Cl-IB-MECA (30 μm), or NaHCO₃ (15 mm). Shown are mean beat frequencies (n = 40–60 cells in 5 experiments, except n = 18–30 cells in three experiments for the B-oligo treatment group). Mean frequencies for untreated controls challenged with Cl-dAdo (6.77 ± 0.53 Hz) or Cl-IB-MECA (5.86 ± 0.56 Hz) were significantly higher than for Ptx-treated cells (3.70 ± 0.15 and 3.17 ± 0.17 Hz). Asterisk indicates p < 0.001.