Biophysical properties of human astrocytic brain tumor cells in cell culture.

For malignant cells cultured from a human astrocytoma, electrophysiological characteristics of the plasma membrane included specific resistivity of 446.82 +/- 279.5 ohm . cm2, specific capacitance of 0.758 +/- 0.52 microfarads/cm2, time constant 0.318 +/- 0.10 msec. The resting membrane potential averaged--14.07 +/- 7.4 mV; the mean input resistance 8.1 +/- 4.0 megohms. The average cell area was 1638 +/- 585 mu2 for contactual and and 1919 +/- 989 mu2 for noncontactual cells. Changes in input resistance and resting membrane potential were observed with increasing time in culture, possibly reflecting cel cycling. There did not appear to be electrical coupling in this cell line.