May 1989
Volume 30, Issue 5
Free
Articles  |   May 1989
Effect of acetylcholine on membrane potential of cultured human nonpigmented ciliary epithelial cells.
Author Affiliations
  • H Helbig
    Institut für Klinische Physiologie, Klinikum Steglitz, Freien Universität Berlin, Federal Republic of Germany.
  • C Korbmacher
    Institut für Klinische Physiologie, Klinikum Steglitz, Freien Universität Berlin, Federal Republic of Germany.
  • J Wohlfarth
    Institut für Klinische Physiologie, Klinikum Steglitz, Freien Universität Berlin, Federal Republic of Germany.
  • M T Coroneo
    Institut für Klinische Physiologie, Klinikum Steglitz, Freien Universität Berlin, Federal Republic of Germany.
  • C Lindschau
    Institut für Klinische Physiologie, Klinikum Steglitz, Freien Universität Berlin, Federal Republic of Germany.
  • P Quass
    Institut für Klinische Physiologie, Klinikum Steglitz, Freien Universität Berlin, Federal Republic of Germany.
  • H Haller
    Institut für Klinische Physiologie, Klinikum Steglitz, Freien Universität Berlin, Federal Republic of Germany.
  • M Coca-Prados
    Institut für Klinische Physiologie, Klinikum Steglitz, Freien Universität Berlin, Federal Republic of Germany.
  • M Wiederholt
    Institut für Klinische Physiologie, Klinikum Steglitz, Freien Universität Berlin, Federal Republic of Germany.
Investigative Ophthalmology & Visual Science May 1989, Vol.30, 890-896. doi:https://doi.org/
  • Views
  • PDF
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      H Helbig, C Korbmacher, J Wohlfarth, M T Coroneo, C Lindschau, P Quass, H Haller, M Coca-Prados, M Wiederholt; Effect of acetylcholine on membrane potential of cultured human nonpigmented ciliary epithelial cells.. Invest. Ophthalmol. Vis. Sci. 1989;30(5):890-896. doi: https://doi.org/.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
This content is PDF only. Please click on the PDF icon to access.
Abstract

Human nonpigmented ciliary epithelial cells (NPE) were grown in tissue culture after transformation with an origin-defective mutant of SV-40 DNA. In these cells membrane potentials (V) were measured using the microelectrode technique. Addition of 10(-4) M acetylcholine led to a bisphasic voltage response. An immediate, transient hyperpolarization was followed by a sustained depolarization below the steady state level. These responses were irreversibly blocked by 10(-5) M atropine. In Ca2+-free media the initial addition of acetylcholine resulted in an unchanged voltage response. A second application of acetylcholine in Ca2+-free solution evoked only an abortive response of V, and further addition had no effect on V. In the presence of Ca2+ channel blockers (10(-5) M verapamil, 1 mM Co2+) the acetylcholine-induced response of the membrane potential was not changed. The initial hyperpolarization induced by acetylcholine was reduced by 33 +/- 3% (n = 6) in the presence of 2 mM Ba2+ and by 79 +/- 6% (n = 6) in the presence of 1 mM quinidine. Moreover, the amplitude of the hyperpolarization was dependent on the extracellular K+ concentration. With increasing extracellular K+ concentration (and decreasing transmembrane K+ gradient) the acetylcholine-induced hyperpolarization was reduced. To further elucidate the role of Ca2+ in the acetylcholine-induced responses, we measured cytoplasmic Ca2+ activity using the fluorescence of intracellularly trapped Fura-2. Cytoplasmic Ca2+ activity increased immediately and transiently upon addition of acetylcholine. We conclude that acetylcholine transiently hyperpolarizes V in cultured human NPE by activation of K+ channels mediated by mobilization of Ca2+ from intracellular stores.

×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×