Figure 2.

HCN channels are involved in the control of MNC electrical excitability. A, Representative traces showing the firing of action potentials of a neuron in control condition and after the superfusion of the cell with 30 μm ZD7288. A1, Mean ± SEM for 12 neurons recorded in each situation. There is a significant decrease in the MNC firing frequency in the presence of ZD7288 compared with control. B, All-points amplitude histograms of 30 s data segments of one representative neuron in the control and in the presence of ZD7288. The date were fitted by a Gaussian function with peaks at −56.5 ± 1.1 mV for the control and −60.6 ± 1.8 mV for ZD7288, representing the values at which neurons spent most of the time in each situation (i.e., the resting membrane potential). A significant hyperpolarization was observed in 9 of 12 cells. B1, Mean values are shown. **p < 0.005 (paired Student's t test). ***p < 0.001 (paired Student's t test).