Role of T-Type Calcium Current in Identified D-Hair Mechanoreceptor Neurons Studied In Vitro

Different subsets of dorsal root ganglion (DRG) mechanoreceptors transduce low- and high-intensity mechanical stimuli. It was shown recently that, in vivo, neurotrophin-4 (NT-4)-dependent D-hair mechanoreceptors specifically express a voltage-activated T-type calcium channel (Ca(v)3.2) that may be r...

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Bibliographic Details
Published in:The Journal of neuroscience 2004-09, Vol.24 (39), p.8480-8484
Main Authors: Dubreuil, Anne-Sophie, Boukhaddaoui, Hassan, Desmadryl, Gilles, Martinez-Salgado, Carlos, Moshourab, Rabih, Lewin, Gary R, Carroll, Patrick, Valmier, Jean, Scamps, Frederique
Format: Article
Language:English
Subjects:
Action Potentials - physiology
Aging - physiology
Animals
Brief Communications
Calcium Channels, T-Type - drug effects
Calcium Channels, T-Type - physiology
Cell Enlargement
Cell Shape
Cells, Cultured
Female
Ganglia, Spinal - cytology
Ganglia, Spinal - physiology
Mechanoreceptors - physiology
Mechanoreceptors - ultrastructure
Mechanotransduction, Cellular - physiology
Membrane Potentials - physiology
Mice
Mice, Knockout
Nerve Growth Factors - genetics
Nerve Growth Factors - physiology
Neurons - physiology
Neurons - ultrastructure
Nickel - pharmacology
Patch-Clamp Techniques
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Summary:Different subsets of dorsal root ganglion (DRG) mechanoreceptors transduce low- and high-intensity mechanical stimuli. It was shown recently that, in vivo, neurotrophin-4 (NT-4)-dependent D-hair mechanoreceptors specifically express a voltage-activated T-type calcium channel (Ca(v)3.2) that may be required for their mechanoreceptive function. Here we show that D-hair mechanoreceptors can be identified in vitro by a rosette-like morphology in the presence of NT-4 and that these rosette neurons are almost all absent in DRG cultures taken from NT-4 knock-out mice. In vitro identification of the D-hair mechanoreceptor allowed us to explore the electrophysiological properties of these cells. We demonstrate that the T-type Ca(v)3.2 channel induced slow membrane depolarization that contributes to lower the voltage threshold for action potential generation and controls spike latency after stimulation of D-hair mechanoreceptors. Indeed, the properties of the T-type amplifier are particularly well suited to explain the high sensitivity of D-hair mechanoreceptors to slowly moving stimuli.
ISSN:0270-6474
1529-2401
DOI:10.1523/JNEUROSCI.1598-04.2004