Biphasic response of human polymorphonuclear leucocytes and keratinocytes (epitheliocytes) from Xenopus laevis to mechanical stimulation

Human polymorphonuclear leucocytes and epitheliocytes isolated from tadpole tails of Xenopus laevis were used to observe the responses of cells to mechanical stimulation with a microneedle. Biphasic responses were observed: a retraction phase lasting 1-3 s was followed by an extension phase lasting 10-40 s. Local or extended loss of cell attachment to the substratum (observed with reflection interference contrast microscopy) preceded changes in cell morphology, visible with phase contrast microscopy. Repeated weak stimulation of one cell side induced extension and locomotion of the cell in this direction. The reported biphasic responses of cells to mechanical stimulation highlight the significance of exact timing when following any cell response to external stimuli.