FIG 4.

The potassium influx induced by cGMP is dependent on a potassium channel. For intracellular potassium flux imaging, KCl (60 mM), cGMP (3 mM), or cAMP (3 mM) was added to the zoospore suspension in the presence or absence of the classic potassium channel inhibitor TEA (at 10 μM). (A) Images from one representative experiment. Cells at the rest state and under bright field are shown at the left of each set of panels. (B) For potassium measurements, the time kinetics of changes in fluorescence emission was recorded. Data are from one representative experiment. (C) Bar graph showing variation in the potassium influx (Δ[K⁺]_i), calculated as peak fluorescence intensity divided by basal fluorescence intensity (F/F0). Data are mean values ± SE for three independent experiments performed in triplicate. *, P < 0.05.