Development of the fast, transient outward K+ current in embryonic sympathetic neurones.
Voltage-activated outward potassium (K+) currents in developing sympathetic neurones, dissociated from the rat superior cervical ganglion (SCG), were studied using the whole-cell patch clamp recording technique. In voltage-clamped neonatal SCG cells, two voltage-dependent K+ currents were measured: the fast, transient K+ current, IA; and, the slower activating, non-inactivating delayed rectifier, IK. Only IK, however, appeared to be present in SCG neurones isolated from early embryonic (E14.5-16.5) rat pups; IA was not observed in these cells. When these embryonic neurones were maintained in cell culture, IA developed over a time course (approximately 4-6 days) similar to that seen in vivo. IA, therefore, which appears to facilitate the fast repolarization phase of the action potential in rat SCG neurones, is the last voltage-activated current to develop in these cells.
D000200:Action Potentials; D000818:Animals; D000831:Animals, Newborn; D002118:Calcium / Q000502:physiology; D002478:Cells, Cultured; D004330:Drosophila; D005728:Ganglia, Sympathetic / Q000196:embryology / Q000502:physiology*; D007473:Ion Channels / Q000502:physiology*; D009431:Neural Conduction; D011188:Potassium / Q000378:metabolism*; D051381:Rats
D007473:Ion Channels; D011188:Potassium; D002118:Calcium