Kv1.3 potassium channels in human alveolar macrophages.
Human alveolar macrophages were obtained from macroscopically normal lung tissue obtained at surgical resections, isolated by adherence, and identified by morphology. Whole cell recordings were made from cells 1-3 h in culture, using electrodes containing potassium chloride. From a holding potential of -100 mV, depolarizing pulses to -40 mV or greater activated an outward current. Tail current reversals showed that this current was potassium selective. Margatoxin completely blocked the current; the concentration giving half-maximal block was 160 pM. In current clamp recordings, the resting membrane potential was -34 mV; margatoxin depolarized cells to close to 0 mV. A pure macrophage population was isolated by fluorescence-activated cell sorting, using the phagocytosis of BODIPY-labeled zymosan particles. Reverse transcription-polymerase chain reaction showed that, of 13 voltage-gated K+ (Kv) potassium channels sought, only Kv1.3 mRNA was present. Margatoxin (1 nM) did not affect the percentage of cells showing phagocytosis sorted from the total population. Under these experimental conditions Kv1.3 sets the resting potential of the cells, but it is not required for Fc receptor-mediated phagocytosis.
Mackenzie
Amanda B
AB
Inst. of Molecular Physiology, Alfred Denny Bldg., Western Bank, Univ. of Sheffield, Sheffield S10 2TN, United Kingdom.
Chirakkal
Hari
H
North
R Alan
RA
D004594:Electrophysiology; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism; D051664:Kv1.3 Potassium Channel; D016676:Macrophages, Alveolar / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D009498:Neurotoxins / Q000494:pharmacology; D009994:Osmolar Concentration; D018408:Patch-Clamp Techniques; D010587:Phagocytosis / Q000187:drug effects; D015221:Potassium Channels / Q000235:genetics / Q000378:metabolism*; D024642:Potassium Channels, Voltage-Gated; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012604:Scorpion Venoms
D007375:Interleukin-1; C496973:KCNA3 protein, human; D051664:Kv1.3 Potassium Channel; D009498:Neurotoxins; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D012333:RNA, Messenger; D012604:Scorpion Venoms; C077910:margatoxin