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The neuropeptide, neuromedin C, activates a potassium current in mouse macrophages

M Ichinose1, N Hara, M Sawada

  • 1Department of Physiology, Shimane Medical University, Izumo, Japan.

FEBS Letters
|December 21, 1992
PubMed

Insights

Neuromedin C (NmC) activates a calcium-dependent potassium current (IK,Ca) in macrophages. This finding suggests NmC can modulate macrophage activity through ion channel regulation.

Area of Science:

  • Cellular electrophysiology
  • Immunology
  • Neuroendocrinology

Background:

  • Macrophages play crucial roles in immune responses.
  • Ion channels are critical regulators of cell function.
  • Neuromedin C (NmC) is a peptide with known biological activities.

Purpose of the Study:

  • To investigate the effect of Neuromedin C (NmC) on ion currents in macrophages.
  • To characterize the nature of the current induced by NmC.

Main Methods:

  • Electrophysiological recordings (outward current) in macrophages.
  • Manipulation of extracellular ion concentrations (K+, Cl-).
  • Application of specific ion channel blockers (TEA, quinidine, ChTX, apamin) and calcium-free solutions.

Main Results:

  • NmC induced an outward current (Io(NmC)) in macrophages.
  • The current's reversal potential depended on external potassium ([K+]o) but not chloride ([Cl-]o).
  • Tetraethylammonium (TEA) and quinidine suppressed Io(NmC), while ChTX and apamin had minimal effect. The current was abolished in Ca(2+)-free conditions.

Conclusions:

  • NmC activates a calcium-dependent potassium current (IK,Ca) in macrophages.
  • This activation mechanism suggests NmC can modulate macrophage activities via ion channel modulation.

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