Title: Differential contribution of the Na(+)-K(+)-2Cl(-) cotransporter NKCC1 to chloride handling in rat embryonic dorsal root ganglion neurons and motor neurons
Authors: Chabwine, J N ×
Talavera PĂ©rez, Karel
Verbert, Leen
Eggermont, Jan
Vanderwinden, J-M
De Smedt, Humbert
Van Den Bosch, Ludo
Robberecht, Wim
Callewaert, Geert #
Issue Date: Apr-2009
Publisher: The Federation of American Societies for Experimental Biology
Series Title: FASEB Journal vol:23 issue:4 pages:1168-1176
Abstract: 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.
ISSN: 0892-6638
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Laboratory of Molecular and Cellular Signaling
Laboratory of Ion Channel Research
Physiology Section (-)
Laboratory of Cell Transport (-)
Research Group Experimental Neurology
Laboratory for Neurobiology (Vesalius Research Center)
Laboratory of Cellular Transport Systems
× corresponding author
# (joint) last author

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