Oscillating and triggering properties of T cell membrane potential.

Using the patch-clamp technique, membrane potential (MP) behaviour under different electrogenic stimuli for both resting and Con A-activated T lymphocytes was studied. The voltage-gated K+ channels stabilize MP at the level of their threshold of activation (-44 +/- 5 mV, n = 27). Upon depolarization of the cell membrane by external current pulse (in the current-clamp mode), MP can oscillate with a high amplitude of 20-50 mV. The amplitude depends on the number of K+ channels per cell and the external current value. After current pulse termination, MP did not return to its initial value, but continued to oscillate. However, the cells first activated by Con A did not display this triggering effect. Thus, the properties of T cell membrane revealed appear to be associated with the functional state of the cell.