Action potentials in human macrophages are calcium spikes.
Transmembrane resting and action potentials measured with single and double microelectrode impalements of human monocyte-derived macrophages reveal that repetitive action potentials induced by depolarizing current pulses are sodium insensitive and calcium dependent. Neither amplitude, frequency of spiking, threshold nor rate of rise of the action potentials is altered by different levels of extracellular sodium, substitution of choline for sodium, or exposure to tetrodotoxin. Spiking activity is enhanced in high calcium, diminished in frequency and amplitude by lowered extracellular calcium and is blocked by cobalt and verapamil.
D000200:Action Potentials / Q000187:drug effects; D002118:Calcium / Q000502:physiology*; D003035:Cobalt / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007473:Ion Channels / Q000502:physiology; D008264:Macrophages / Q000502:physiology*; D008564:Membrane Potentials; D012964:Sodium / Q000502:physiology; D014700:Verapamil / Q000494:pharmacology
D007473:Ion Channels; D003035:Cobalt; D012964:Sodium; D014700:Verapamil; D002118:Calcium