Abstract
Voltage-gated calcium channels (Ca(v)) are tonically up-regulated via Ras/extracellular signal-regulated kinase (ERK) signalling in sensory neurones. However, the mechanisms underlying the specificity of cellular response to this pathway remain unclear. Neurotrophic factors are attractive candidates to be involved in this process as they are key regulators of ERK signalling and have important roles in neuronal survival, development and plasticity. Here, we report that in rat dorsal root ganglion neurones, endogenous nerve growth factor (NGF), glial derived neurotrophic factor (GDNF) and epidermal growth factor (EGF) are all involved in tonic ERK-dependent up-regulation of Ca(v) channels. Chronic (overnight) deprivation of growth factors inhibits total Ca(v) current according to developmental changes in expression of the cell surface receptors for NGF, GDNF and EGF. Whilst EGF specifically regulates transcriptional expression of Ca(v)s, NGF and GDNF also acutely modulate Ca(v) channels within a rapid ( approximately 10min) time-frame. These acute effects likely involve changes in the biophysical properties of Ca(v)s, including altered channel gating rather than changes in surface expression. Furthermore, NGF, GDNF and EGF differentially regulate specific populations of Ca(v)s. Thus, ERK-dependent regulation of Ca(v) activity provides an elegant and extremely flexible system with which to tailor calcium influx to discrete functional demands.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Animals, Newborn
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Calcium Channels / drug effects
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Calcium Channels / genetics
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Calcium Channels / metabolism*
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Cell Membrane / drug effects
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Cell Membrane / genetics
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Cell Membrane / metabolism
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Cells, Cultured
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Epidermal Growth Factor / metabolism
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Epidermal Growth Factor / pharmacology
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Extracellular Signal-Regulated MAP Kinases / drug effects
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Extracellular Signal-Regulated MAP Kinases / metabolism*
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Ganglia, Spinal / drug effects
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Ganglia, Spinal / metabolism*
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Glial Cell Line-Derived Neurotrophic Factor / metabolism
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Glial Cell Line-Derived Neurotrophic Factor / pharmacology
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Intercellular Signaling Peptides and Proteins / metabolism*
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Intercellular Signaling Peptides and Proteins / pharmacology
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Ion Channel Gating / drug effects
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Ion Channel Gating / genetics*
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Membrane Potentials / drug effects
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Membrane Potentials / genetics
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Nerve Growth Factor / metabolism
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Nerve Growth Factor / pharmacology
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Neurons, Afferent / drug effects
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Neurons, Afferent / metabolism*
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Patch-Clamp Techniques
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Rats
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Rats, Sprague-Dawley
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Signal Transduction / drug effects
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Signal Transduction / genetics
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Transcriptional Activation / drug effects
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Transcriptional Activation / genetics
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Up-Regulation / drug effects
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Up-Regulation / genetics
Substances
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Calcium Channels
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Glial Cell Line-Derived Neurotrophic Factor
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Intercellular Signaling Peptides and Proteins
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Epidermal Growth Factor
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Nerve Growth Factor
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Extracellular Signal-Regulated MAP Kinases