Leishmania amazonensis infection induces changes in the electrophysiological properties of macrophage-like cells

Whole cell patch-clamp recordings were used to study the electrical propert ies of the macrophage-like cell line J774.1, after infection with Leishmani a amazonensis. Infection induced a significant increase in cell size and me mbrane capacitance, suggesting that parasite invasion leads to the addition of plasma membrane to the host cell. By 24 hr after infection, the host ce ll membrane potential was significantly more hyperpolarized than control ce lls, and this difference remained for the subsequent 72 hr post-infection. The hyperpolarization was paralleled by an increase in the density of inwar d rectifying K+ currents. The shape of the conductance vs. voltage curve, t he kinetic properties and the pharmacological profile of these currents wer e not significantly altered by infection. These results suggest that infect ion by L. amazonensis causes an increase in the number of functional inward rectifying K+ channels, leading to hy perpolarization of the host cell mem brane.