Abnormal GABA(A) receptor-mediated currents in dorsal root ganglion neurons isolated from Na-K-2Cl cotransporter null mice

K. W. Sung, M. Kirby, Michael Mcdonald, D. M. Lovinger, E. Delpire

Research output: Contribution to journalArticle

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Abstract

We have recently disrupted Slc12a2, the gene encoding the secretory Na-K-2Cl cotransporter in mice (NKCC1) (Delpire et al., 1999). Gramicidin perforated-patch and whole-cell recordings were performed to study GABA-induced currents in dorsal root ganglion (DRG) neurons isolated from wild-type and homozygote NKCC1 knock-out mice. In wild-type DRG neurons, strong GABA-evoked inward current was observed at the resting membrane potential, suggesting active accumulation of Cl- in these cells. This GABA-induced current was blocked by picrotoxin, a GABA(A) receptor blocker. The strong Cl- accumulation that gives rise to depolarizing GABA responses is caused by Na-K-2Cl cotransport because reduction of external Cl- or application of bumetanide induced a decrease in [Cl-](i), whereas an increase in external K+ caused an apparent [Cl-](i) accumulation. In contrast to control neurons, little or no net current was observed at the resting membrane potential in homozygote NKCC1 mutant DRG neurons. E(GABA) was significantly more negative, demonstrating the absence of Cl- accumulation in these cells. Application of bumetanide induced a positive shift of E(GABA), suggesting the presence of an outward Cl- transport mechanism. In agreement with an absence of GABA depolarization in DRG neurons, behavioral analysis revealed significant alterations in locomotion and pain perception in the knock-out mouse. Our results clearly demonstrate that the Na-K-2Cl co-transporter is responsible for [Cl-](i) accumulation in DRG neurons and that via regulation of intracellular Cl-, the Na-K-2Cl cotransporter participates in the modulation of GABA neurotransmission and sensory perception.

Original languageEnglish (US)
Pages (from-to)7531-7538
Number of pages8
JournalJournal of Neuroscience
Volume20
Issue number20
StatePublished - Oct 15 2000
Externally publishedYes

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Spinal Ganglia
GABA-A Receptors
gamma-Aminobutyric Acid
Neurons
Bumetanide
Homozygote
Knockout Mice
Membrane Potentials
Sodium-Potassium-Chloride Symporters
Symporters
Gramicidin
GABAergic Neurons
Picrotoxin
Pain Perception
Patch-Clamp Techniques
Locomotion
Synaptic Transmission
Genes

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)

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Abnormal GABA(A) receptor-mediated currents in dorsal root ganglion neurons isolated from Na-K-2Cl cotransporter null mice. / Sung, K. W.; Kirby, M.; Mcdonald, Michael; Lovinger, D. M.; Delpire, E.

In: Journal of Neuroscience, Vol. 20, No. 20, 15.10.2000, p. 7531-7538.

Research output: Contribution to journalArticle

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