Differential contribution of the Na(+)-K(+)-2Cl(-) cotransporter NKCC1 to chloride handling in rat embryonic dorsal root ganglion neurons and motor neurons
| Autor: | Geert Callewaert, H De Smedt, Wim Robberecht, Jan Eggermont, Joelle N Chabwine, J.-M. Vanderwinden, Leen Verbert, Karel Talavera, L. Van Den Bosch |
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| Jazyk: | angličtina |
| Rok vydání: | 2009 |
| Předmět: |
Patch-Clamp Techniques
Sodium-Potassium-Chloride Symporters Biology Biochemistry Dorsal root ganglion Sodium Potassium Chloride Symporter Inhibitors Chlorides Receptors GABA Ganglia Spinal Genetics medicine Extracellular Premovement neuronal activity Animals Patch clamp Molecular Biology Bumetanide Cells Cultured gamma-Aminobutyric Acid Membrane potential Motor Neurons Models Statistical Gramicidin Depolarization Rats Inbred Strains Embryo Mammalian Receptors GABA-A Immunohistochemistry Anti-Bacterial Agents Rats Electrophysiology Kinetics medicine.anatomical_structure Biophysics Cotransporter Biotechnology medicine.drug |
| Popis: | Plasma membrane chloride (Cl(-)) pathways play an important role in neuronal physiology. Here, we investigated the role of NKCC1 cotransporters (a secondary active Cl(-) uptake mechanism) in Cl(-) handling in cultured rat dorsal root ganglion neurons (DRGNs) and motor neurons (MNs) derived from fetal stage embryonic day 14. Gramicidin-perforated patch-clamp recordings revealed that DRGNs accumulate intracellular Cl(-) through a bumetanide- and Na(+)-sensitive mechanism, indicative of the functional expression of NKCC1. Western blotting confirmed the expression of NKCC1 in both DRGNs and MNs, but immunocytochemistry experiments showed a restricted expression in dendrites of MNs, which contrasts with a homogeneous expression in DRGNs. Both MNs and DRGNs could be readily loaded with or depleted of Cl(-) during GABA(A) receptor activation at depolarizing or hyperpolarizing membrane potentials. After loading, the rate of recovery to the resting Cl(-) concentration (i.e., [Cl(-)](i) decrease) was similar in both cell types and was unaffected by lowering the extracellular Na(+) concentration. In contrast, the recovery on depletion (i.e., [Cl(-)](i) increase) was significantly faster in DRGNs in control conditions but not in low extracellular Na(+). The experimental observations could be reproduced by a mathematical model for intracellular Cl(-) kinetics, in which DRGNs show higher NKCC1 activity and smaller Cl(-)-handling volume than MNs. On the basis of these results, we conclude that embryonic DRGNs show a higher somatic functional expression of NKCC1 than embryonic MNs. The high NKCC1 activity in DRGNs is important for maintaining high [Cl(-)](i), whereas lower NKCC1 activity in MNs allows large [Cl(-)](i) variations during neuronal activity. ispartof: FASEB Journal vol:23 issue:4 pages:1168-1176 ispartof: location:United States status: published |
| Databáze: | OpenAIRE |
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