Na(v)1.5 sodium channels in a human microglial cell line.
Microglial cells are the major immuno-competent cells in the mammalian brain where they play a crucial role in maintaining the CNS environment in the face of various potentially pathological insults. We have used electrophysiological and pharmacological methods to study a microglial cell line (C13-NJ) derived from the human CNS. In whole-cell patch clamp experiments we identified an inward current that exhibited biophysical hallmarks of a classical voltage-gated Na(+) channel. This identification was confirmed by further experiments in which the current was eliminated by removal of Na(+) from the bathing medium. Relatively weak inhibition by TTX (30+/-3% at 500nM) and sensitivity to 100microM Zn(2+) suggested that this current was predominantly mediated by the cardiac sodium channel isoform Na(V)1.5. Sodium current density was not altered by treatment with either lipopolysaccharide or beta-amyloid 1-42. The presence of the Na(V)1.5 subunit in microglial cells is discussed with respect to its reported roles in phagocytosis, proliferation and migration of other non-cardiac cells.
Nicholson
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MRC Centre for Synaptic Plasticity, University of Bristol, School of Medical Sciences, Bristol, BS8 1TD, UK. Elizabeth.Nicholson@bristol.ac.uk
Randall
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D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D017628:Microglia / Q000166:cytology* / Q000378:metabolism / Q000502:physiology*; D009124:Muscle Proteins / Q000037:antagonists & inhibitors / Q000502:physiology*; D032383:Myocytes, Cardiac / Q000378:metabolism / Q000502:physiology; D062554:NAV1.5 Voltage-Gated Sodium Channel; D026941:Sodium Channel Blockers / Q000494:pharmacology; D015222:Sodium Channels / Q000502:physiology*
D009124:Muscle Proteins; D062554:NAV1.5 Voltage-Gated Sodium Channel; C568320:SCN5A protein, human; D026941:Sodium Channel Blockers; D015222:Sodium Channels