CBD concentration dependence and varying pulse duration F-I curve measurement. (a and b) Show voltage dependence of activation (control: −19.9 ± 4.2 mV, z = 2.8 ± 0.3, n = 5; 1 µM: V_1/2 = −14.3 ± 4.2 mV, z = 2.8 ± 0.3, n = 5; 2 µM: V_1/2 = −21.2 ± 8.1 mV, z = 3.2 ± 0.4, n = 4; P > 0.05 for both V_1/2 and z for both 1 and 2 µM CBD) and 200-ms F-I curve (control: V_1/2 = −64.1 ± 2.4 mV, z = −2.7 ± 0.3, n = 8; 1 µM: V_1/2 = −72.7 ± 3.0 mV, z = −2.8 ± 0.4, n = 5; 2 µM: V_1/2 = −75.5 ± 0.8 mV, z = −2.2 ± 0.5, n = 3; P = 0.0281 for V_1/2 and P > 0.05 for z [1 µM] and P = 0.0073 for V_1/2 and P > 0.05 for z [2 µM]) at 0, 1, and 2 µM CBD. Statistical tests were performed for either CBD concentrations against control/0 µM CBD. (c and d) Voltage dependence of F-I curve from 200 ms (control: V_1/2 = −64.1 ± 2.4 mV, z = −2.7 ± 0.3, n = 8; CBD 1 µM: V_1/2 = −72.7 ± 3.0 mV, z = −2.8 ± 0.4, n = 5; P = 0.0281 for V_1/2 and P > 0.05 for z) and 800 ms (control: V_1/2 = −64.9 ± 1.2 mV, z = −2.1 ± 0.2, n = 4; CBD 1 µM: V_1/2 = −70.9 ± 1.3 mV, z = −1.9 ± 0.2, n = 4; P < 0.05 for V_1/2 and P > 0.05 for z).