Ceramide, a putative second messenger for nerve growth factor, modulates the TTX-resistant Na+ current and delayed rectifier K+ current in rat sensory neurons

Research output: Contribution to journalArticle

129 Citations (Scopus)

Abstract

Because nerve growth factor (NGF) is elevated during inflammation and is known to activate the sphingomyelin signalling pathway, we examined whether NGF and its putative second messenger, ceramide, could modulate the excitability of capsaicin-sensitive adult and embryonic sensory neurons. Using the whole-cell patch-clamp recording technique, exposure of isolated sensory neurons to either 100 ng ml-1 NGF or 1 μM N-acetyl sphingosine (C2-ceramide) produced a 3- to 4-fold increase in the number of action potentials (APs) evoked by a ramp of depolarizing current in a time-dependent manner. Intracellular perfusion with bacterial sphingomyelinase (SMase) also increased the number of APs suggesting that the release of native ceramide enhanced neuronal excitability. Glutathione, an inhibitor of neutral SMase, completely blocked the NGF-induced augmentation of AP firing, whereas dithiothreitol, an inhibitor of acidic SMase, was without effect. In the presence of glutathione and NGF, exogenous ceramide still enhanced the number of evoked APs, indicating that the sensitizing action of ceramide was downstream of NGF. To investigate the mechanisms of action for NGF and ceramide, isolated membrane currents were examined. Both NGF and ceramide facilitated the peak amplitude of the TTX-resistant sodium current (TTX-RINa) by approximately 1.5-fold and shifted the activation to more hyperpolarized voltages. In addition, NGF and ceramide suppressed an outward potassium current (IK) by ∼35 %. Ceramide reduced IK in a concentration-dependent manner. Isolation of the NGF- and ceramide-sensitive currents indicates that they were delayed rectifier types of IK. The inflammatory prostaglandin, PGE2, produced an additional suppression of IK after exposure to ceramide (∼35%), suggesting that these agents might act on different targets. Thus, our findings indicate that the pro-inflammatory agent, NGF, can rapidly enhance the excitability of sensory neurons. This NGF-induced sensitization is probably mediated by activation of the sphingomyelin signalling pathway to liberate ceramide(s), wherein ceramide appears to be the second messenger involved in modulating neuronal excitability.

Original languageEnglish
Pages (from-to)385-402
Number of pages18
JournalJournal of Physiology
Volume544
Issue number2
DOIs
StatePublished - Oct 15 2002

Fingerprint

Ceramides
Second Messenger Systems
Nerve Growth Factor
Sensory Receptor Cells
Sphingomyelin Phosphodiesterase
Action Potentials
Sphingomyelins
Glutathione
Architectural Accessibility
Sphingosine
Dithiothreitol
Capsaicin
Patch-Clamp Techniques
Evoked Potentials
Dinoprostone
Prostaglandins
Potassium
Perfusion
Sodium

ASJC Scopus subject areas

  • Physiology

Cite this

@article{97c29e97cc164ad6a610dbb71a4fe08a,
title = "Ceramide, a putative second messenger for nerve growth factor, modulates the TTX-resistant Na+ current and delayed rectifier K+ current in rat sensory neurons",
abstract = "Because nerve growth factor (NGF) is elevated during inflammation and is known to activate the sphingomyelin signalling pathway, we examined whether NGF and its putative second messenger, ceramide, could modulate the excitability of capsaicin-sensitive adult and embryonic sensory neurons. Using the whole-cell patch-clamp recording technique, exposure of isolated sensory neurons to either 100 ng ml-1 NGF or 1 μM N-acetyl sphingosine (C2-ceramide) produced a 3- to 4-fold increase in the number of action potentials (APs) evoked by a ramp of depolarizing current in a time-dependent manner. Intracellular perfusion with bacterial sphingomyelinase (SMase) also increased the number of APs suggesting that the release of native ceramide enhanced neuronal excitability. Glutathione, an inhibitor of neutral SMase, completely blocked the NGF-induced augmentation of AP firing, whereas dithiothreitol, an inhibitor of acidic SMase, was without effect. In the presence of glutathione and NGF, exogenous ceramide still enhanced the number of evoked APs, indicating that the sensitizing action of ceramide was downstream of NGF. To investigate the mechanisms of action for NGF and ceramide, isolated membrane currents were examined. Both NGF and ceramide facilitated the peak amplitude of the TTX-resistant sodium current (TTX-RINa) by approximately 1.5-fold and shifted the activation to more hyperpolarized voltages. In addition, NGF and ceramide suppressed an outward potassium current (IK) by ∼35 {\%}. Ceramide reduced IK in a concentration-dependent manner. Isolation of the NGF- and ceramide-sensitive currents indicates that they were delayed rectifier types of IK. The inflammatory prostaglandin, PGE2, produced an additional suppression of IK after exposure to ceramide (∼35{\%}), suggesting that these agents might act on different targets. Thus, our findings indicate that the pro-inflammatory agent, NGF, can rapidly enhance the excitability of sensory neurons. This NGF-induced sensitization is probably mediated by activation of the sphingomyelin signalling pathway to liberate ceramide(s), wherein ceramide appears to be the second messenger involved in modulating neuronal excitability.",
author = "Zhang, {Y. H.} and Michael Vasko and Grant Nicol",
year = "2002",
month = "10",
day = "15",
doi = "10.1113/jphysiol.2002.024265",
language = "English",
volume = "544",
pages = "385--402",
journal = "Journal of Physiology",
issn = "0022-3751",
publisher = "Wiley-Blackwell",
number = "2",

}

TY - JOUR

T1 - Ceramide, a putative second messenger for nerve growth factor, modulates the TTX-resistant Na+ current and delayed rectifier K+ current in rat sensory neurons

AU - Zhang, Y. H.

AU - Vasko, Michael

AU - Nicol, Grant

PY - 2002/10/15

Y1 - 2002/10/15

N2 - Because nerve growth factor (NGF) is elevated during inflammation and is known to activate the sphingomyelin signalling pathway, we examined whether NGF and its putative second messenger, ceramide, could modulate the excitability of capsaicin-sensitive adult and embryonic sensory neurons. Using the whole-cell patch-clamp recording technique, exposure of isolated sensory neurons to either 100 ng ml-1 NGF or 1 μM N-acetyl sphingosine (C2-ceramide) produced a 3- to 4-fold increase in the number of action potentials (APs) evoked by a ramp of depolarizing current in a time-dependent manner. Intracellular perfusion with bacterial sphingomyelinase (SMase) also increased the number of APs suggesting that the release of native ceramide enhanced neuronal excitability. Glutathione, an inhibitor of neutral SMase, completely blocked the NGF-induced augmentation of AP firing, whereas dithiothreitol, an inhibitor of acidic SMase, was without effect. In the presence of glutathione and NGF, exogenous ceramide still enhanced the number of evoked APs, indicating that the sensitizing action of ceramide was downstream of NGF. To investigate the mechanisms of action for NGF and ceramide, isolated membrane currents were examined. Both NGF and ceramide facilitated the peak amplitude of the TTX-resistant sodium current (TTX-RINa) by approximately 1.5-fold and shifted the activation to more hyperpolarized voltages. In addition, NGF and ceramide suppressed an outward potassium current (IK) by ∼35 %. Ceramide reduced IK in a concentration-dependent manner. Isolation of the NGF- and ceramide-sensitive currents indicates that they were delayed rectifier types of IK. The inflammatory prostaglandin, PGE2, produced an additional suppression of IK after exposure to ceramide (∼35%), suggesting that these agents might act on different targets. Thus, our findings indicate that the pro-inflammatory agent, NGF, can rapidly enhance the excitability of sensory neurons. This NGF-induced sensitization is probably mediated by activation of the sphingomyelin signalling pathway to liberate ceramide(s), wherein ceramide appears to be the second messenger involved in modulating neuronal excitability.

AB - Because nerve growth factor (NGF) is elevated during inflammation and is known to activate the sphingomyelin signalling pathway, we examined whether NGF and its putative second messenger, ceramide, could modulate the excitability of capsaicin-sensitive adult and embryonic sensory neurons. Using the whole-cell patch-clamp recording technique, exposure of isolated sensory neurons to either 100 ng ml-1 NGF or 1 μM N-acetyl sphingosine (C2-ceramide) produced a 3- to 4-fold increase in the number of action potentials (APs) evoked by a ramp of depolarizing current in a time-dependent manner. Intracellular perfusion with bacterial sphingomyelinase (SMase) also increased the number of APs suggesting that the release of native ceramide enhanced neuronal excitability. Glutathione, an inhibitor of neutral SMase, completely blocked the NGF-induced augmentation of AP firing, whereas dithiothreitol, an inhibitor of acidic SMase, was without effect. In the presence of glutathione and NGF, exogenous ceramide still enhanced the number of evoked APs, indicating that the sensitizing action of ceramide was downstream of NGF. To investigate the mechanisms of action for NGF and ceramide, isolated membrane currents were examined. Both NGF and ceramide facilitated the peak amplitude of the TTX-resistant sodium current (TTX-RINa) by approximately 1.5-fold and shifted the activation to more hyperpolarized voltages. In addition, NGF and ceramide suppressed an outward potassium current (IK) by ∼35 %. Ceramide reduced IK in a concentration-dependent manner. Isolation of the NGF- and ceramide-sensitive currents indicates that they were delayed rectifier types of IK. The inflammatory prostaglandin, PGE2, produced an additional suppression of IK after exposure to ceramide (∼35%), suggesting that these agents might act on different targets. Thus, our findings indicate that the pro-inflammatory agent, NGF, can rapidly enhance the excitability of sensory neurons. This NGF-induced sensitization is probably mediated by activation of the sphingomyelin signalling pathway to liberate ceramide(s), wherein ceramide appears to be the second messenger involved in modulating neuronal excitability.

UR - http://www.scopus.com/inward/record.url?scp=0037107437&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0037107437&partnerID=8YFLogxK

U2 - 10.1113/jphysiol.2002.024265

DO - 10.1113/jphysiol.2002.024265

M3 - Article

C2 - 12381813

AN - SCOPUS:0037107437

VL - 544

SP - 385

EP - 402

JO - Journal of Physiology

JF - Journal of Physiology

SN - 0022-3751

IS - 2

ER -