Importance of the IK for consecutive synaptic transmission. (A-B) Rod bipolar cells were stimulated by 65 pA injection for two times with 10, 110, and 210 ms interval in the current-clamp mode. The synaptic currents were recorded in the AII amacrine cells with a −70 mV holding potential. In the rod bipolar cells, the secondary peak membrane potential (blue arrow) reduced at 10 ms interval, and it recovered similarly with the first stimulation from 110 ms, in both the control (A, upper traces) and clotrimazole application (B, upper traces) traces. Recovery of the secondary post-synaptic current (red arrow) compared to first synaptic current from AII amacrine cells was more reduced in the clotrimazole application group (B, lower traces) than in the control group (A, lower traces). (C) Time course of the secondary peak membrane potential in the rod bipolar cells. We presented relative secondary peak membrane potential compared to the first peak membrane potential of the rod bipolar cells. Both the control (black line) and clotrimazole-treated groups showed a decrease at the 10 ms interval pulse and recovered around 95% from the 100 ms interval (n = 4, P > 0.05, multiple t-test). (D) Time course of the secondary synaptic current of the AII amcrine cells. Here, we present the secondary synaptic current relative to the synaptic current. Both the control (black line) and clotrimazole-treated groups showed a decrease at the 10 ms interval pulse. However, after the 60 ms interval, the control group showed more recovery of the secondary synaptic current than the clotrimazole-treated group did. (n = 4, *P < 0.05, multiple t-test).