Potassium-Coupled Chloride Cotransport Controls Intracellular Chloride in Rat Neocortical Pyramidal Neurons

摘要: Chloride (Cl(-)) homeostasis is critical for many cell functions including signaling and volume regulation. The action of GABA at GABA(A) receptors primarily determined by the concentration intracellular Cl(-). Developmental regulation Cl(-) results in a depolarizing response to immature neocortical neurons hyperpolarizing or shunting mature neurons. One protein that participates neuron-specific K(+)-Cl(-) cotransporter (KCC2). Thermodynamic considerations predict physiological ranges extracellular K(+) concentrations, KCC2 can act either extrude accumulate To test this hypothesis, we examined function pyramidal cells from rat slices (18-28 d postnatal) (3-6 rats. Intracellular was estimated reversal potential whole-cell currents evoked local application exogenous GABA. Both increasing decreasing resulted concomitant change inhibition furosemide caused depended on pipette Cl(-); recordings with low Cl(-), lowered whereas elevated raised In neonatal rats, manipulation had no effect concentration, consistent minimal mRNA levels observed animals. These data demonstrate physiologically relevant developmentally regulated role via both extrusion accumulation.