title: Regulation of Na+,K+ pump activity by nerve growth factor in chick embryo dorsal root ganglion cells.
abstract: Nerve growth factor (NGF) is required for the growth and development of sensory and sympathetic neurons. Incubation of chick dorsal root ganglionic cells without NGF resulted in a decrease of active (Na+,K+-pump-mediated) K+ influx over a period of several hours. Addition of NGF to NGF-deprived cells caused 1) a return of the active K+ influx to the values occurring in cells continuously exposed to NGF, preceded by 2) a very rapid, but transient overstimulation of the Na+,K+-pump-mediated K+ influx. Restoration of normal Na+,K+-pump activity occurred at NGF concentrations of 1 biological unit/ml or greater, whereas the NGF concentration in the 1-100 biological unit/ml range affected the rapidity with which the pump restoration took place. The transient pump behavior was only observed in NGF-deprived cells and could not be elicited in NGF-supported steady-state cells or in cells having already received delayed NGF once. This transient Na+,K+-pump behavior was exclusively displayed in conjunction with a high intracellular Na+ concentration. Decreasing the external Na+ concentration below 70 mM reduced the hyperstimulation response to NGF, until at 10 mM Na+ the delayed presentation of NGF caused no overshoot at all. The effect of NGF on the Na+,K+-pump was specific for the NGF molecule and could not be mimicked by other proteins.
mesh_terms: D000818:Animals; D002642:Chick Embryo; D046508:Culture Techniques; D004305:Dose-Response Relationship, Drug; D005727:Ganglia, Spinal / Q000201:enzymology*; D007700:Kinetics; D009414:Nerve Growth Factors / Q000494:pharmacology*; D011188:Potassium / Q000502:physiology; D012964:Sodium / Q000502:physiology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
chemical_list: D009414:Nerve Growth Factors; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium