Figure 3. I_CatSper, but not ATP-activated P2X2 current, is reduced in CatSperz-null spermatozoa.

(A) CatSperz-/- and (B) CatSperz+/- I_CatSper. Left panels show the current-voltage relations of monovalent I_CatSper in response to voltage ramps at the time points indicated. Right traces are representative time courses of I_CatSper measured in the standard bath solution (1, HS), ATP-activated P2X2 current (2, ATP), and nominally divalent-free solution (3, DVF) at −100 mV (gray circles) and +100 mV (black circles). I_CatSper in CatSperz-null sperm cells is ~60% of that recorded from wt. Inward I_ATP current induced by 100 µM ATP is similar in both phenotypes and indistinguishable from previously published wt I_ATP (Navarro et al., 2011). (C) Average I_CatSper measured from CatSperz+/- (−683 ± 77 pA) and CatSperz-/- (−426 ± 50 pA) sperm cells at −100 mV. Data are mean ± SEM. p=0.0297. Cartoon shows the standard pipette solution (mM); internal Cs used to block K⁺ currents.

DOI: http://dx.doi.org/10.7554/eLife.23082.012