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J Neurosci. 2016 Jan 27;36(4):1386-400. doi: 10.1523/JNEUROSCI.3535-15.2016.

Dynamics of Phosphoinositide-Dependent Signaling in Sympathetic Neurons.

Author information

1
Department of Physiology and Biophysics, University of Washington, Seattle, Washington 98195, and.
2
ATK Innovation, Analytics and Discovery, North Bend, Washington 98045.
3
Department of Physiology and Biophysics, University of Washington, Seattle, Washington 98195, and hille@u.washington.edu.

Abstract

In neurons, loss of plasma membrane phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] leads to a decrease in exocytosis and changes in electrical excitability. Restoration of PI(4,5)P2 levels after phospholipase C activation is therefore essential for a return to basal neuronal activity. However, the dynamics of phosphoinositide metabolism have not been analyzed in neurons. We measured dynamic changes of PI(4,5)P2, phosphatidylinositol 4-phosphate, diacylglycerol, inositol 1,4,5-trisphosphate, and Ca(2+) upon muscarinic stimulation in sympathetic neurons from adult male Sprague-Dawley rats with electrophysiological and optical approaches. We used this kinetic information to develop a quantitative description of neuronal phosphoinositide metabolism. The measurements and analysis show and explain faster synthesis of PI(4,5)P2 in sympathetic neurons than in electrically nonexcitable tsA201 cells. They can be used to understand dynamic effects of receptor-mediated phospholipase C activation on excitability and other PI(4,5)P2-dependent processes in neurons.

SIGNIFICANCE STATEMENT:

Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] is a minor phospholipid in the cytoplasmic leaflet of the plasma membrane. Depletion of PI(4,5)P2 via phospholipase C-mediated hydrolysis leads to a decrease in exocytosis and alters electrical excitability in neurons. Restoration of PI(4,5)P2 is essential for a return to basal neuronal activity. However, the dynamics of phosphoinositide metabolism have not been analyzed in neurons. We studied the dynamics of phosphoinositide metabolism in sympathetic neurons upon muscarinic stimulation and used the kinetic information to develop a quantitative description of neuronal phosphoinositide metabolism. The measurements and analysis show a several-fold faster synthesis of PI(4,5)P2 in sympathetic neurons than in an electrically nonexcitable cell line, and provide a framework for future studies of PI(4,5)P2-dependent processes in neurons.

KEYWORDS:

M-current; PI(4,5)P2; excitability; phosphoinositide metabolism; superior cervical ganglion neurons

PMID:
26818524
PMCID:
PMC4728732
DOI:
10.1523/JNEUROSCI.3535-15.2016
[Indexed for MEDLINE]
Free PMC Article

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