Electric Currents Associated With Directed Migration of Fibroblasts

¹ Department of Physiology, Kyoto University Faculty of Medicine, Kyoto 606, Japan

Cultured mouse fibroblasts (L cells) respond to a complement subcomponent, Clq, with hyperpolarizations and exhibit chemotaxis toward this ligand. Using a vibrating probe extracellular recording technique, we have studied whether extracellular electric currents are associated with directed migration or chemotaxis of the fibroblasts. The fibroblasts under directed migration were obtained in wounded monolayer cultures. Extracellular electric currents were too small to be detected around these migrating cells by means of a vibrating platinum black electrode (about 30 µm in diameter). To converge the current around migrating cells to a narrow space, a disk-like coverslip (with a central hole of 1 mm in diameter) was laid over wounded cultures. Thus, sizable electric currents (0.1-2.4 µA/cm²) could be recorded at an aperture opening of the coverslip on wounded cultures in a weakly conductive medium. The currents always flowed to the leading front of the migrating cells. No current was detected on non-migrating fibroblasts. A chemoattractant (Clq) added in front of migrating cells induced biphasic changes in the electric current.