KINETICS OF A-CURRENTS IN SYMPATHETIC PREGANGLIONIC NEURONS AND GLIAL-CELLS

TRANSIENT outward currents (A-currents; LA) were recorded in sympathet ic preganglionic neurones (SPNs) and glial cells of the intermediolate ral cell column (IML) by whole-cell recordings in rat spinal cord slic es. In both cell types IA activated at around -45 mV and the timecours e of decay was monoexponential, but faster in glial cells than in neur ones. In both cases decay time constants displayed the same increase w ith 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 monoex ponential decay in neurones and glial cells, respectively.