Activity Dependent Expression of Na+/K+ Pump Isoforms in Dorsal Root Ganglia Neurons

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Activity dependent expression of Na+/K+ pump isoforms in dorsal root ganglia neurons. (PI Dobretsov M., NSF proposal # 9904815)Lay AbstractNeurons communicate information as sequences of electrical signals. The modality of the message is determined by the neuronal connections, while the message itself is coded by the number and frequency of signals within the sequence. One of the problems faced by neurons is that the transmission of each signal is followed by an accumulation of Na+ in the cell. If it is not removed from the neuron this accumulated Na+ may affect characteristics of the entire sequence of signals and of the whole message itself. It appears, therefore, that neuronal function should strongly depend on the activity of the Na+/K+ pump, the ion transporter that has a major role in maintaining stable concentrations of Na+ and K+ inside animal cells. Furthermore, it appears that the activity and/or characteristics of the Na+/K+ pump should differ in neurons with different discharge intensity and different needs in intracellular Na+ control. However, aside from theoretical considerations, little is known about actual relationship existing between the neuron signaling and sodium influx into the neuron, isoform expression, and characteristics of the neuronal Na+/K+ pump. These questions will be addressed in the present investigation that will use the rat peripheral neurons as a neuronal model, and electrophysiological, histological, and fluorescent imaging techniques as tools to characterize neuronal function and expression of the Na+/K+ pump.