Fig. 9.

Somato-dendritic distribution and properties of low-threshold calcium channels. A, Selected averaged traces demonstrating the relationship between current amplitude and recording location. Note that the transient inward current is of the same kinetics at each recording location, but of relatively greater amplitude when recorded from stem dendrites. Somatic and stem dendritic patches were taken from the same neuron. B, Pooled data quantifying the relationship between current density and dendritic location. Each recording is shown as an open circle.Filled squares show mean (±SD) current as a function of distance from the soma (±SD) for recordings made from the soma, stem dendrites, primary branch points, and higher order dendrites (fromleft to right, respectively).C, Steady-state activation and inactivation curves constructed from data pooled by recording location, as shown in theinset. Note that more distal dendritic recordings yield activation and inactivation curves that are shifted to the right along the voltage axis. Voltages are relative to resting membrane potential.