Figure 10.

Blocking effect of K⁺ conductance with 4-AP reverses the APB-induced reduction of H1 HC light responses. (A) Outward current responses to red light (2 × 10⁶ quanta/μm²/s) recorded under whole-cell voltage clamp from an H1 HC. Application of 20 μM L-APB induced an outward current and reduction of light responses. Coapplication of 200 μM 4-AP induced an inward current, accompanied by some recovery of the light responses. V _h = −60 mV. (B) The L-APB–induced reduction in light response amplitude (open bars) and sEPSC rate (filled bars) showed some recovery with 4-AP. The sEPSC rate was similarly determined as in Fig. 5 B.