The activation of transient receptor potential vanilloid receptor subtype 1 by capsaicin without extracellular Ca2+ is involved in the mechanism of distinct substance P release in cultured rat dorsal root ganglion neurons

2007 ◽  
Vol 377 (4-6) ◽  
pp. 325-332 ◽  
Author(s):  
He-Bin Tang ◽  
Yoshihiro Nakata
Keyword(s):  
Dorsal Root ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Dorsal Root Ganglion Neurons ◽  
Receptor Subtype ◽  
Transient Receptor Potential Vanilloid ◽  
P Release ◽  
Transient Receptor ◽  
Ganglion Neurons ◽  
Substance P Release

scholarly journals Propofol Modulates Agonist-induced Transient Receptor Potential Vanilloid Subtype-1 Receptor Desensitization via  a Protein Kinase Cϵ-dependent Pathway in Mouse Dorsal Root Ganglion Sensory Neurons

2010 ◽  
Vol 113 (4) ◽  
pp. 833-844 ◽  
Author(s):  
Peter J. Wickley ◽  
Ryo Yuge ◽  
Mary S. Russell ◽  
Hongyu Zhang ◽  
Michael A. Sulak ◽  
...  
Keyword(s):  
Dorsal Root Ganglion ◽  
Sensory Neurons ◽  
Dorsal Root ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Dorsal Root Ganglion Neurons ◽  
Transient Receptor Potential Vanilloid ◽  
Wild Type ◽  
Transient Receptor ◽  
Ganglion Neurons

Background The activity of transient receptor potential vanilloid subtype-1 (TRPV1) receptors, key nociceptive transducers in dorsal root ganglion sensory neurons, is enhanced by protein kinase C epsilon (PKCepsilon) activation. The intravenous anesthetic propofol has been shown to activate PKCepsilon. Our objectives were to examine whether propofol modulates TRPV1 function in dorsal root ganglion neurons via activation of PKCepsilon. Methods Lumbar dorsal root ganglion neurons from wild-type and PKC& epsilon;-null mice were isolated and cultured for 24 h. Intracellular free Ca concentration was measured in neurons by using fura-2 acetoxymethyl ester. The duration of pain-associated behaviors was also assessed. Phosphorylation of PKCepsilon and TRPV1 and the cellular translocation of PKCepsilon from cytosol to membrane compartments were assessed by immunoblot analysis. Results In wild-type neurons, repeated stimulation with capsaicin (100 nm) progressively decreased the transient rise in intracellular free Ca concentration. After desensitization, exposure to propofol rescued the Ca response. The resensitizing effect of propofol was absent in neurons obtained from PKCepsilon-null mice. Moreover, the capsaicin-induced desensitization of TRPV1 was markedly attenuated in the presence of propofol in neurons from wild-type mice but not in neurons from PKCepsilon-null mice. Propofol also prolonged the duration of agonist-induced pain associated behaviors in wild-type mice. In addition, propofol increased phosphorylation of PKCepsilon as well as TRPV1 and stimulated translocation of PKCepsilon from cytosolic to membrane fraction. Discussion Our results indicate that propofol modulates TRPV1 sensitivity to capsaicin and that this most likely occurs through a PKCepsilon-mediated phosphorylation of TRPV1.

scholarly journals Long-Term Diabetic Microenvironment Augments the Decay Rate of Capsaicin-Induced Currents in Mouse Dorsal Root Ganglion Neurons

Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 775
Author(s):  
Xingjuan Chen ◽  
Yaqian Duan ◽  
Ashley Riley ◽  
Megan Welch ◽  
Fletcher White ◽  
...  
Keyword(s):  
Peripheral Neuropathy ◽  
Dorsal Root Ganglion ◽  
Patch Clamp ◽  
Dorsal Root ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Dorsal Root Ganglion Neurons ◽  
Transient Receptor Potential Vanilloid ◽  
Drg Neurons ◽  
Ganglion Neurons

Individuals with end-stage diabetic peripheral neuropathy present with decreased pain sensation. Transient receptor potential vanilloid type 1 (TRPV1) is implicated in pain signaling and resides on sensory dorsal root ganglion (DRG) neurons. We investigated the expression and functional activity of TRPV1 in DRG neurons of the Ins2+/Akita mouse at 9 months of diabetes using immunohistochemistry, live single cell calcium imaging, and whole-cell patch-clamp electrophysiology. 2′,7′-Dichlorodihydrofluorescein diacetate (DCFH-DA) fluorescence assay was used to determine the level of Reactive Oxygen Species (ROS) in DRGs. Although TRPV1 expressing neuron percentage was increased in Ins2+/Akita DRGs at 9 months of diabetes compared to control, capsaicin-induced Ca2+ influx was smaller in isolated Ins2+/Akita DRG neurons, indicating impaired TRPV1 function. Consistently, capsaicin-induced Ca2+ influx was decreased in control DRG neurons cultured in the presence of 25 mM glucose for seven days versus those cultured with 5.5 mM glucose. The high glucose environment increased cytoplasmic ROS accumulation in cultured DRG neurons. Patch-clamp recordings revealed that capsaicin-activated currents decayed faster in isolated Ins2+/Akita DRG neurons as compared to those in control neurons. We propose that in poorly controlled diabetes, the accelerated rate of capsaicin-sensitive TRPV1 current decay in DRG neurons decreases overall TRPV1 activity and contributes to peripheral neuropathy.

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