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. 2019 Dec 27;39(4):e102723. doi: 10.15252/embj.2019102723

Figure 3. Dynamics of CNGK activation and cGMP hydrolysis.

Figure 3

  1. Time course of the change in voltage V m evoked by a 2‐ms light flash in sperm that was loaded with caged cGMP (15 μM) and recorded in 100KASW. Inset: extended timescale showing the rise of V m. Fit of data (black) using two exponentials with time constants τrise = 17.4 ms and τrelax = 354 ms. Light flash in all panels is depicted as dashed magenta line.
  2. Time course of the changes in V m evoked by 100‐ms flash in 100KASW using caged cGMP (blue) and caged 8‐Br‐cGMP (black). The flashes released 260 nM cGMP or 2,600 nM 8‐Br‐cGMP.
  3. Time course of changes in V m in 100KASW evoked by 2‐s flashes at different light energy that corresponds to 440, 220, 75, and 8 nM/s of cGMP. Data were fitted using a heuristic model described by equation [Link] (Materials and Methods section) (black lines).
  4. Amplitude (red) and decay time τrelax (black) for different light energies and release rates for experiments as shown in panel C. τrelax was determined using a single exponential fit. The linear fit of the V m amplitude was restricted to low light levels; at higher levels, the V m response saturates (see panel C). Points indicate mean ± SD from five experiments.