Nonlinear current-voltage relationships in cultured macrophages.

Abstract

Intracellular recordings of cultured mouse thioglycolate-induced peritoneal exudate macrophages revealed that these cells can exhibit 2 different types of electrophysiological properties characterized by differences in their current-voltage relationships and their resting membrane potentials. The majority of cells had low resting membrane potentials (-20 to -40 mV) and displayed current-voltage relationships that were linear for inward-going current pulses and rectifying for outward-going pulses. Small depolarizing transients, occurring spontaneously or induced by current pulses, were seen in some cells and low resting membrane potentials. A 2nd smaller group of cells exhibited more hyperpolarized resting membrane potentials (-60 to -90 mV) and S-shaped current-voltage relationships associated with a high-resistance transitional region. Cells with S-shaped current-voltage relationships sometimes exhibited 2 stable states of membrane potential on either side of the high-resistance transitional region. Macrophages apparently exhibit complex electrophysiological properties often associated with excitable cells.