Fig. 2.
Comparison of the conductance and calcium dependence of somatic, dendritic, and nerve terminal BK channels. A, mean conductance of somatic, dendritic, and nerve terminal channels measured in the presence of 5 and 10 μM free Ca2+. B, normalized NPo-voltage relationship of SON somatic and dendritic channels compared with SON nerve terminal channels in 10 μM free Ca2+ (S.E.M. not shown to reduce clutter). Somatic, dendritic, and nerve terminal are shown as triangles, squares, and circles, respectively. C, plots of normalized mean NPo as a function of voltage at different [Ca2+]i; circles, 5 μM; squares, 10 μM; triangles, 25 μM. Open and filled symbols, soma and dendrite, respectively. The NPo-V relationship, fitted with a Boltzmann equation, is shifted along the voltage axis to more negative potentials as [Ca2+]i increases.