Electrophysiological properties of macrophages.
Electrophysiological studies indicate that the macrophage can display at least two different K conductances, a Ca-mediated K conductance and an inward rectifying K conductance, as well as an electrogenic Na+-K+ pump. Spontaneous hyperpolarizations associated with a Ca-mediated K permeability have been noted in all types of macrophages studied. Similar membrane hyperpolarizations can be elicited by a variety of stimuli that presumably increase intracellular calcium. These include mechanical and electrical stimulation as well as exposure to endotoxin-activated serum, chemotactic peptides, and the Ca ionophore A23187. Recent patch clamp studies on macrophages demonstrated channel activity that probably corresponds to currents through the inward rectifying K conductance previously described with current clamp techniques. With the advent of the patch clamp, this and other conductances can be effectively examined by using both whole-cell voltage clamp and patch recordings in a variety of different macrophages, including small freshly isolated cells.
D000200:Action Potentials; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002463:Cell Membrane Permeability; D002478:Cells, Cultured; D004553:Electric Conductivity; D006168:Guinea Pigs; D006801:Humans; D007473:Ion Channels / Q000502:physiology; D008264:Macrophages / Q000502:physiology*; D008564:Membrane Potentials; D051379:Mice; D011188:Potassium / Q000378:metabolism; D051381:Rats; D012964:Sodium / Q000378:metabolism
D007473:Ion Channels; D012964:Sodium; D011188:Potassium; D002118:Calcium