Kinetics of A-currents in sympathetic preganglionic neurones and glial cells

Transient outward currents (A-currents; IA) were recorded in sympathetic preganglionic neurones (SPNs) and glial cells of the intermediolateral cell column (IML) by whole-cell recordings in rat spinal cord slices. In both cell types IA activated at around -45 mV and the time-course of decay was monoexponential, but faster in glial cells than in neurones. In both cases decay time constants displayed the same increase with depolarization above -30 mV. In neurones, the activation curve was shifted to more negative value along the voltage axis and was steeper than the activation curve for glial cells whereas inactivation curves were similar. Recovery from inactivation followed a double and monoexponential decay in neurones and glial cells, respectively.