Figure 2. K_Ca channels, particularly of the SK type, control the rate of intrinsic activity of DCN neurons.

Aa, the spontaneous activity of a DCN neuron as large-conductance K_Ca (BK) channels were blocked with 100 nm iberiotoxin. Ab, the firing rate of DCN neurons before (control) and after application of iberiotoxin. The continuous line denotes unity. Ac, predominant and maximum spontaneous firing rates of individual cells together with the averages in the presence and absence of iberiotoxin. *P < 0.05, n = 14 cells. Ad, the coefficient of variation of the interspike intervals for the same cells shown in Ac. Ba, blockade of small-conductance (SK) K_Ca channels with 100 nm apamin increased the firing rate and resulted in high-frequency bursts of action potentials. Bb, the firing rate of DCN neurons before (control) and after application of apamin. The continuous line denotes unity. Bc, predominant and maximum spontaneous firing rates of individual cells together with the averages in the presence and absence of 20 μm EBIO (n = 7) or 100 nm apamin (n = 14). *P < 0.001. Bd, the coefficient of variation of the interspike intervals for the same cells shown in Bc. *P < 0.001. n.s., not significant.