Mechanical activation of dorsal root ganglion cells in vitro: Comparison with capsaicin and modulation by κ-opioids

Juergen M. Gschossmann, Victor V. Chaban, James A. McRoberts, Helen E Raybould, Steven H. Young, Helena S. Ennes, Tony Lembo, Emeran A. Mayer

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

The aim of this study was to characterize plasma membrane pathways involved in the intracellular calcium ([Ca2+](i)) response of small DRG neurons to mechanical stimulation and the modulation of these pathways by κ-opioids. [Ca2+](i) responses were measured by fluorescence video microscopy of Fura-2 labeled lumbosacral DRG neurons obtained from adult rats in short-term primary culture. Transient focal mechanical stimulation of the soma, or brief superfusion with 300 nM capsaicin, resulted to [Ca2+](i) increases which were abolished in Ca2+-free solution, but unaffected by lanthanum (25 μM) or tetrodotoxin (10-6 M). 156 out of 465 neurons tested (34%) showed mechanosensitivity while 55 out of 118 neurons (47%) were capsaicin-sensitive. Ninty percent of capsaicin-sensitive neurons were mechanosensitive. Gadolinium (Gd3+; 250 μM) and amiloride (100 μM) abolished the [Ca2+](i) transient in response to mechanical stimulation, but had no effect on capsaicin-induced [Ca2+](i) transients. The κ-opioid agonists U50,488 and fedotozine showed a dose-dependent inhibition of mechanically stimulated [Ca2+](i) transients but had little effect on capsaicin-induced [Ca2+](i) transients. The inhibitory effect of U50,488 was abolished by the κ-opioid antagonist nor-Binaltorphimine dihydrochloride (nor-BNI; 100 nM), and by high concentrations of naloxone (30-100 nM), but not by low concentrations of naloxone (3 nM). We conclude that mechanically induced [Ca2+](i) transients in small diameter DRG somas are mediated by influx of Ca2+ through a Gd3+- and amiloride-sensitive plasma membrane pathway that is co-expressed with capsaicin-sensitive channels. Mechanical-, but not capsaicin-mediated, Ca2+ transients are sensitive to κ-opioid agonists. Copyright (C) 2000 Elsevier Science B.V.

Original languageEnglish (US)
Pages (from-to)101-110
Number of pages10
JournalBrain Research
Volume856
Issue number1-2
DOIs
StatePublished - 2000

Keywords

  • κ-Opioid receptor
  • Capsaicin
  • Dorsal root ganglia
  • Fedotozine
  • Mechanostimulation

ASJC Scopus subject areas

  • Neuroscience(all)

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  • Cite this

    Gschossmann, J. M., Chaban, V. V., McRoberts, J. A., Raybould, H. E., Young, S. H., Ennes, H. S., Lembo, T., & Mayer, E. A. (2000). Mechanical activation of dorsal root ganglion cells in vitro: Comparison with capsaicin and modulation by κ-opioids. Brain Research, 856(1-2), 101-110. https://doi.org/10.1016/S0006-8993(99)02353-7