Oxygen Sensing pp 241-248

Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 475)

Chemosensing at the Carotid Body

Involvement of a HERG-like potassium current in glomus cells
  • Jeffrey L. Overholt
  • Eckhard Ficker
  • Tianen Yang
  • Hashim Shams
  • Gary R. Bright
  • Nanduri R. Prabhakar
Chapter

Abstract

Currently, it is notclear what type of K+ channel(s) is active at the resting membrane potential (RMP) in glomus cells of the carotid body (CB). HERO channels produce currents that are known to contribute to the RMP in other neuronal cells. The goal of the present study was to determine whether CB glomus cells express HERG-like (HL) K1 current, and if so, to determine whether HL currents regulate the RMP. With high [K+][1] depolarizing voltage steps from −85mV revealed a slowly deactivating inward tail current indicative of HL K+ current in whole-cell, voltage clamped glomus cells. The HL currents were blocked by dofetilide (DOF) in a concentration-dependent manner (IC50 13 nM) and high concentrations (1 and 10 mM) ofBa21. The steady-state activation properties of the HL current (Vh=− mV) suggest that it is active at the R M P in glomus cells. Whole-cell, current clamped glomus cells exhibited a RMP of −48mV. 150 nM DOF caused a significant (14 mV) depolarizing shift in the RMP. In isolated glomus cells, [Ca2−+], increased in response to DOF (1 μM). In an in-vitro CB preparation, DOF increased basal sensory discharge in a concentration-dependent manner and significantly attenuated the sensory response to hypoxia. These results suggest that the HERG-like current is responsible for controlling the RMP in glomus cells of the rabbit CB, and that it is involved in the chemosensory response to hypoxia of the CB.

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Copyright information

© Kluwer Academic Publishers 2002

Authors and Affiliations

  • Jeffrey L. Overholt
    • 1
  • Eckhard Ficker
    • 1
  • Tianen Yang
    • 1
  • Hashim Shams
    • 1
  • Gary R. Bright
    • 1
  • Nanduri R. Prabhakar
    • 1
  1. 1.Department of Physiology and BiophysicsCase Western Reserve UniversityCleveland
  2. 2.Institute fur PhysiologieRuhr-Universitat BochumGermany

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