Nerve growth factor enhances the excitability of rat sensory neurons through activation of the atypical protein kinase C isoform, PKMζ

Y. H. Zhang, J. Kays, K. E. Hodgdon, T. C. Sacktor, Grant Nicol

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Our previous work showed that nerve growth factor (NGF) increased the excitability of small-diameter capsaicin-sensitive sensory neurons by activating the p75 neurotrophin receptor and releasing sphingolipid-derived second messengers. Whole cell patch-clamp recordings were used to establish the signaling pathways whereby NGF augments action potential (AP) firing (i.e., sensitization). Inhibition of MEK1/2 (PD-98059), PLC (U-73122, neomycin), or conventional/novel isoforms of PKC (bisindolylmaleimide I) had no effect on the sensitization produced by NGF. Pretreatment with a membrane-permeable, myristoylated pseudosubstrate inhibitor of atypical PKCs (aPKCs: PKMζ, PKCζ, and PKCλ/i) blocked the NGF-induced increase in AP firing. Inhibitors of phosphatidylinositol 3-kinase (PI3K) also blocked the sensitization produced by NGF. Isolated sensory neurons were also treated with small interfering RNA (siRNA) targeted to PKCζ. Both Western blots and quantitative real-time PCR established that PKMζ, but neither full-length PKCζ nor PKCλ/i, was significantly reduced after siRNA exposure. Treatment with these labeled siRNA prevented the NGF- induced enhancement of excitability. Furthermore, consistent with the high degree of catalytic homology for aPKCs, internal perfusion with active recombinant PKCζ or PKCi augmented excitability, recapitulating the sensitization produced by NGF. Internal perfusion with recombinant PKCζ suppressed the total potassium current and enhanced the tetrodotoxin-resistant sodium current. Pretreatment with the myristoylated pseudosubstrate inhibitor blocked the increased excitability produced by ceramide or internal perfusion with recombinant PKCζ. These results demonstrate that NGF leads to the activation of PKMζ that ultimately enhances the capacity of small- diameter capsaicin-sensitive sensory neurons to fire APs through a PI3K-dependent signaling cascade.

Original languageEnglish
Pages (from-to)315-335
Number of pages21
JournalJournal of Neurophysiology
Volume107
Issue number1
DOIs
StatePublished - Jan 2012

Fingerprint

Nerve Growth Factor
Sensory Receptor Cells
Protein Isoforms
Phosphatidylinositol 3-Kinase
Small Interfering RNA
Perfusion
Capsaicin
Action Potentials
Nerve Growth Factor Receptor
Sphingolipids
Neomycin
PKC-3 protein
Ceramides
Tetrodotoxin
Second Messenger Systems
Real-Time Polymerase Chain Reaction
Potassium
Western Blotting
Sodium
Membranes

Keywords

  • Action potential
  • Neuronal firing
  • P75 neurotrophin receptor
  • Sensitization

ASJC Scopus subject areas

  • Physiology
  • Neuroscience(all)

Cite this

Nerve growth factor enhances the excitability of rat sensory neurons through activation of the atypical protein kinase C isoform, PKMζ. / Zhang, Y. H.; Kays, J.; Hodgdon, K. E.; Sacktor, T. C.; Nicol, Grant.

In: Journal of Neurophysiology, Vol. 107, No. 1, 01.2012, p. 315-335.

Research output: Contribution to journalArticle

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